# Changelog

All notable changes to this project will be documented in this file.

The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).

## [Unreleased]

### Added
- **Folder Library — a bundled core plugin (`plugins/folder_library/`) that browses the DLC library by its on-disk folder tree.** Surfaces top-level folders → subfolders → songs (root-level songs land in `(Unsorted)`), with in-app folder management (create / rename / delete nested folders), song moves via dialog or drag-and-drop, and sort/filter that mirrors the host library's filter state. Wired into both the classic (v2) library toolbar and the v3 Songs page as a third **Folders** view alongside grid/tree; the plugin's `screen.js` is loaded once by the host and reused (idempotent IIFEs). Supersedes the former standalone "Folder Organizer" community plugin (removed from the README list). Backend (`routes.py`) registers `/api/plugins/folder_library/{tree,folder/create,folder/rename,folder/delete,song/move}`; **all filesystem mutations are confined to `DLC_DIR` and validated against path traversal** (per-segment name validation plus a resolved-containment check on `song/move`), and folder deletion relocates every song — de-duplicating colliding names — so a name clash never destroys a song. A two-level cache keeps re-opening folders fast. Tests: `tests/plugins/folder_library/test_routes.py` (path-safety helpers + move-traversal and delete-no-data-loss end-to-end).
- **Full-screen (immersive) plugin screens — opt-in via `"fullscreen": true` in `plugin.json`.** DAW-style plugin UIs (e.g. a practice studio) need the whole viewport, not a scrolling content page below the topbar — embedded in the v3 shell they get cut off at the bottom with dead space up top. A plugin can now declare a top-level `"fullscreen": true`; `plugins/__init__.py` surfaces it as the `fullscreen` boolean on `/api/plugins` (mirroring the `settings_category` plumbing). When such a plugin's screen is active, `static/v3/shell.js` toggles `html.fb-immersive` from `syncActive()` (so it tracks every navigation incl. deep-link), and `static/v3/v3.css` hides the topbar, collapses the sidebar to a functional **icon rail** (kept reachable — Escape is bound only on player/settings scopes, so a fully-hidden sidebar would trap the user), and lets the active plugin screen fill `#v3-main`. Mirrors the existing `ss-follower-pre` chrome-hide pattern. Additive + opt-in: plugins without the flag are unaffected. Tests: `tests/test_plugins.py::test_fullscreen_flag_parsed_from_manifest`.
- **Achievements wall sync — background drain worker (epic PR3, client side).** The bundled `achievements` plugin gains a dead-letter sync worker that POSTs queued Feat unlocks (and removals) to the hosted **feedback-achievements** wall service (separate repo). Idle unless a wall URL is configured (`FEEDBACK_ACHIEVEMENTS_WALL_URL`); uses `requests` with the baked-in client-token header, mirroring `lib/lyrics_transcribe`'s outbound pattern (explicit timeout, no raise on non-2xx). **Dead-letter, never drop** (pure `engine.drain_decision`): network error / `429` / `5xx` → keep `pending` (retry); other `4xx` → `dead_letter` (diagnosable, replayable); `2xx` → delete on server ack. A row leaves the queue only on ack or a user opt-out. `remove-me` now enqueues a wall removal keyed by the reused `player_hash`. Verified by an end-to-end staging round-trip (earn a Feat → drains onto the wall with name + short hash → `remove-me` → wall empties) with **no IP** in tables or access logs. Tests: `tests/plugins/achievements/test_sync.py` (decision table + ack/retry/dead-letter retention + four-field payload on the wire). The hosted service itself (FastAPI + SQLite-on-disk, Feats-only, hidden-until-first-global-unlock, profanity filter, in-memory rate limit, Render blueprint, migration tool) lives in the new `feedback-achievements` repo.
- **Achievements wall — opt-in, privacy controls & data-minimization gate (epic PR2).** Sharing earned **Feats** on the (forthcoming) public wall is strictly opt-in. A new **onboarding step** (`static/v3/profile.js`, inserted after song-directory / before instrument paths — the wizard is now five steps) presents a plain-language card: it publishes only your display name and the Feats you earn, never songs/skills/scores, and is **off by default**. The bundled plugin's Settings panel (`plugins/achievements/settings.html`, mounted under the **System** tab via `settings.category`) carries the same toggle plus a **"Remove me from the wall"** button (`POST /api/plugins/achievements/remove-me` — wipes local synced state offline + enqueues a wall removal). Core adds `achievements_enabled` (bool, default `false`) to `_default_settings()` + the `/api/settings` validation block + `_RESETTABLE_SETTINGS_KEYS` in `server.py`, mirrored to `localStorage` in `app.js loadSettings()`. **Data-minimization contract (binding, code-enforced):** every outbound payload is built by a single explicit-dict serializer (`engine.build_wall_payload`, never `dict(row)`/`**model`) whose key-set is **exactly** `{display_name, player_hash, achievement_id, unlocked_at}` with `achievement_id` always a **Feat** id — a unit test asserts the four-field set and goes red on a fifth. Enqueue is doubly gated: it happens only when opted-in **and** a profile identity (name + the reused `player_hash`) exists; **competency unlocks never enqueue** (integration law). Tests: `tests/plugins/achievements/test_datamin.py` (key-set, opt-out/identity/competency gating) + `tests/test_settings_api.py` (flag persists/validates/resettable).
- **Achievements & Feats of Power — local engine + tabbed Profile (epic PR1).** The Profile screen (`static/v3/profile.js`) becomes **tabbed** exactly like the v3 Settings page (`.fb-tabbar` / `.fb-tab[data-tab]` / `.fb-tabpanel[data-tab]`, active-tab persisted in `localStorage 'v3-profile-tab'`): a **Profile** (main) tab carrying the existing header + best-scores cards plus a new **Feats of Power** trophy shelf mount (`#v3-profile-feats-slot`, earned-only / hidden-until-earned), and an **Achievements** tab with a plugin mount (`#v3-profile-achievements-mount`) + `[data-empty-for]` empty note. Core dispatches a new **`v3:profile-rendered`** event after every render (mirrors `v3:settings-rendered`) so the plugin re-injects on each profile entry. A new bundled **`plugins/achievements/`** plugin owns the engine: SQLite under `<config_dir>/achievements/achievements.db` (`unlocks` / `counters` / `comp_ledger` / `sync_queue`), pure threshold/criterion math in the testable sibling `engine.py` (P-V), and routes under `/api/plugins/achievements/` (`activity`, `report-unlock`, `report-criterion`, `catalog`, `earned`, `feats`, `remove-me`). **Two surfaces, one engine, structurally separated (integration law):** **Feats** (activity/volume — Note Hunter, Marathon, Untouchable, Road Warrior, Time Served, Encore, two 🥚 secrets) read activity counters only, evaluated from a batched `song:ended` activity POST (notes only when **notedetect** is present — graceful degradation, no fake progress); **competency Achievements** (baseline: First Steps / Ascendant / Steady Hands / Renaissance + per-instrument Apprentice·Journeyman·Master / Personal Best / Challenger) are evaluated from **progression events only** and never re-derived from activity. The Achievements catalogue is always shown (locked = greyed), grouped by a secondary pill row over the **real progression paths** (Global / Guitar / Bass / Drums / Keys — auto-extends to new paths) with a per-category "X / Y earned" badge, defaulting to the player's primary path. Source plugins contribute their own competency defs and report unlocks through a versioned **`window.feedBack.achievements`** API (`register`/`registerAll`/`unlock`/`progress`), load-order-safe via the `window.__feedBackAchievementsPending` queue + an `achievements:ready` event (minigames pending-queue pattern); an absent source contributes nothing (no dead greyed rows). Opt-in publishing to a hosted Feats wall, the Settings privacy toggle, and the data-minimization gate land in epic PR2/PR3. Tests: `tests/plugins/achievements/test_engine.py` + `test_routes.py` (incl. the integration-law assertion that a competency unlock never reaches the Feats shelf).
- **v3 settings page redesigned as a tabbed, card-row layout.** The single long scrolling settings screen becomes a horizontal tab bar (Gameplay / Audio / Graphics / Keybinds / Progression / Mic / Plugins / System) over card rows — each a leading icon + title + description with the control (toggle/dropdown/slider) on the right, plus a per-category "Reset" action. The markup lives in `static/v3/index.html` (so existing element ids keep hydrating through the unchanged `app.js` `loadSettings()`/`persistSetting()` path); a new `static/v3/settings.js` owns tab switching + active-tab persistence (`localStorage 'v3-settings-tab'`), the per-category reset, and a read-only **Keybinds** reference built from the live shortcut registry (`window.getAllShortcuts()`); styling is plain CSS in `static/v3/v3.css` (no Tailwind rebuild). **Plugins choose their settings tab** via a new optional `settings.category` field in `plugin.json` (`plugins/__init__.py` surfaces it as `settings_category`; `app.js` mounts each plugin's `<details>` panel into `#plugin-settings-<category>`, falling back to the generic Plugins tab) — `highway_3d` ships `category: "graphics"`; the out-of-repo notedetect/progression plugins should declare `"mic"` / `"progression"`. **New gameplay settings:** **Countdown before song** (a four-beat count-in before playback, wired end-to-end via the existing count-in engine + the song-start autostart path; key `countdown_before_song`, default off); **Miss penalty** (`miss_penalty`) and **Fail behavior** (`fail_behavior`) are persisted now but not yet consumed by scoring (shown with a "Not yet active" badge). "Note highway speed" surfaces the existing `master_difficulty` and stays in sync with the player-popover difficulty slider. New `POST /api/settings/reset` clears chosen keys back to defaults. Tests: `tests/test_settings_api.py` (new keys + reset), `tests/test_plugins.py::test_settings_category_parsed_from_manifest`, `tests/browser/settings-tabbed.spec.ts`.
- **Full-mix audio exposed alongside stems for the stem mixer's auto-switch.** `lib/sloppak.py::load_song` now parses the optional manifest `original_audio:` key (the single pre-separation mixdown, e.g. `original/full.ogg`) into a new `LoadedSloppak.original_audio` field, with the same path-traversal guard and permissive "missing → disabled" posture as the `drum_tab` loader. The highway WS `song_info` frame additively carries three new fields next to `stems`: `original_audio_url` (served by the existing `/api/sloppak/{filename}/file/{rel_path}` endpoint, `None` when the pack ships stems only), `has_original_audio`, and `has_stems` (mirroring the `has_drum_tab`/`has_keys` flag convention). The stems plugin consumes `original_audio_url` to play the untouched single file while every stem slider is at unity and switch to the separate stems the moment one drops below 100%. **Migration notes:** the `song_info` message shape is a stable contract — these are purely additive; all existing fields are unchanged. `audio_url` still points at stem[0] when stems exist (it is only the degraded native fallback); the one behavioural change is that a stem-less, full-mix-only sloppak now sets `audio_url` to the full mix instead of emitting `audio_error`, so it plays natively.
- **Autoplay & auto-exit — a global "click it, it plays; finish, you're back at the menu" option (default ON).** New single Settings toggle (`autoplayExit` in `localStorage`, surfaced in both the v3 and classic settings screens; absence of the key = enabled) that closes the friction at both ends of the play loop. **Autoplay:** `playSong()` previously loaded a chart paused, requiring a Play press; a one-shot flag armed per fresh load is now consumed by the next `song:ready` (highway.js) to auto-start via the existing `togglePlay()` path (HTML5 + `_juceMode` + count-in). Arrangement switches / seeks reuse the same `song:ready` event but never arm the flag, so they don't auto-restart. **Auto-exit:** on `song:ended`, core returns to the launching menu after a short grace delay — unless a visible full-screen results/dialog overlay is on top (detected via `[role=dialog][aria-modal]` / `.fixed.inset-0` with a `getClientRects()` visibility test that works for `position:fixed`), in which case the return is deferred so that score screen's own Close button (calling `window.closeCurrentSong()`) drives the exit. A plugin can also defer explicitly via the new `window.feedBack.holdAutoExit()` (called synchronously from its own `song:ended` handler — core's listener runs first). Both paths mean **no external plugin PR is required** for a results screen to be respected. **Context-aware destination:** the player's remembered origin (`_playerOriginScreen`) now honours any real launch screen instead of clamping to library/home/favorites, and a one-shot `window.feedBack.setReturnScreen(id)` override lets the lessons catalog (`static/v3/lessons.js`) send a finished lesson back to the lessons screen — not the song library — even though the external tutorials plugin owns the `playSong` call. Also exposes a read-only `window.feedBack.autoplayExit` getter for plugins. Songs and lessons share the same `playSong` → highway path, so both inherit the behaviour. Core-only (`static/app.js`, `static/v3/lessons.js`, both `index.html`s); the end-of-song score screen itself remains a plugin. Optional polish (not required — the overlay heuristic already covers it): external scoring/note-detection plugins (e.g. SlopScale) may call `holdAutoExit()` + `closeCurrentSong()` for an exact, heuristic-free handoff.
- **"Song Editor" promoted to a first-class v3 sidebar item.** The editor
  plugin (`id: editor`) now gets its own dedicated sidebar entry — under the
  Library group, just below Songs — via the existing `PROMOTED_PLUGINS`
  mechanism in `static/v3/shell.js`, instead of being reachable only through
  the generic Plugins gallery. Gated on the plugin actually being installed
  (`renderPromotedNav` checks `/api/plugins`), so it appears only when the
  editor is loaded. The displayed label comes from the plugin's manifest
  `nav.label`.
- **Guitar Pro → notation importer (`lib/gp2notation.py`)** (feedBack#825 WS4b, epic #828). Piano/keys tracks imported from Guitar Pro (GPIF: `.gpx` GP6 / `.gp` GP7-8) now produce real Sloppak Notation Format data (sloppak-spec §5.3) alongside the `midi = string*24 + fret` guitar wire encoding. `gp2rs_gpx.convert_file` writes a `<stem>.notation.json` sidecar next to each keys arrangement XML (best-effort — a notation bug never breaks the RS-XML conversion), and `gp2notation.attach_notation_to_sloppak()` is the assembly-side helper that renames it into `notation_<id>.json` + adds the per-arrangement `notation:` manifest sub-key. Voice→staff routing salvages the logic from PR #703 (whose `stf` wire-field approach this supersedes): GP voice position 0 → `rh` staff (`G2`), positions ≥ 1 → `lh` (`F4`); a forced-LH track (the merged `Piano LH` partner from `_find_piano_pairs`, or a standalone track named `… LH`) routes everything to `lh` — preserving authored hand crossings instead of inferring hands from pitch. Emits measures with absolute `t` from the bar-indexed tempo map, change-only `ts`/`tempo`/`ks`, and `beat_groups` for compound/irregular meters (6/8 → `[3,3]`, 9/8 → `[3,3,3]`, 5/8 → `[2,3]`, 7/8 → `[2,2,3]` — cf. the feedBack#261 denominator pitfalls); beats carry `dur`/`dot`/`tu`/`rest` from GP rhythms and notes carry absolute `midi` (String+Fret resolves via the string template's concert pitches, Tone+Octave via `(octave+1)*12 + step`) with `tied` continuations kept as real beats (engraving needs the tied notehead — unlike the RS-XML walk, which drops them and extends sustain). Timing reuses the `gp2rs_gpx` machinery (bar-indexed tempo map, per-beat rhythm durations, `_note_midi`) so notation lines up with the RS XML the highway plays — with one deliberate divergence: double dots advance time ×1.75 (vs. the RS-XML walk's single-dot ×1.5 approximation) so a written `dot: 2` agrees with the emitted beat times; sharing the walk itself stays tracked in feedBack#618. Tests: `tests/test_gp2notation.py`.
- **Legacy keys → notation lifter (`scripts/lift_keys_notation.py`)** (feedBack#825 WS4c, epic #828). One-time batch converter that lifts existing **directory-form** piano/keys sloppaks from the legacy guitar wire encoding (`midi = s*24 + f`) into real Sloppak Notation Format files (sloppak-spec §5.3). Candidates are arrangements whose name matches `\b(keys|piano|keyboard|synth)\b` (case-insensitive); each gets a `notation_<id>.json` plus the per-arrangement `notation:` manifest sub-key. Measures derive from the song-level `beats` downbeats (`measure >= 0`; `song_timeline.json` preferred, first-arrangement fallback), with per-measure tempo from downbeat spacing (emitted only on a > 1 BPM change). Durations come from the wire sustain (`sus`, legacy `l` alias) when present, else the gap to the next onset in the same hand — quantized to the nearest plain/single-dotted `{1,2,4,8,16,32}` denominator at the local tempo, floored at a 32nd. Hands are split heuristically: onsets within 10 ms form a group; a group spanning > 12 semitones splits at its largest internal interval gap (low side → `lh`), otherwise the whole group goes by mean pitch vs middle C — single-staff output when everything lands on one hand. Idempotent (arrangements already carrying `notation:` are skipped; an orphan `notation_<id>.json` without the manifest key is refused, not overwritten) with `--dry-run` support; every payload is checked via `notation.validate_notation` before write. Honest caveat: the manifest is round-tripped through PyYAML (`safe_load` + `safe_dump(sort_keys=False)`) — key order survives, YAML comments/custom formatting do not (the script warns when comments are present). Zip-form `.sloppak` files are reported and skipped. Tests: `tests/test_lift_keys_notation.py`.
- **Notation schema v1 freeze — completeness batch** (feedBack#822, epic #828). Adds the low-hanging-fruit fields ahead of content production: top-level credits `rights`/`lyricist`/`arranger`; measure `pickup` (anacrusis); beat `arp` (arpeggiate), `ferm` (fermata), and **typed grace notes** — `grace: "a"` (acciaccatura, MusicXML `grace/@slash=yes`) / `"p"` (appoggiatura); note `stem` (`"up"`/`"down"` force). Pedal is settled as the existing `spd`/`sph`/`spu` trio with a documented MusicXML `<pedal start|change|stop>` mapping — no separate `ped` field. A new "v1 non-features" spec subsection pins the accepted limitations (microtonal, figured bass, mid-measure key/time/clef changes, `ott`/`barline`/ornaments/`trem`/`glis`) as additive-v1.x territory. `lib/notation.py` gains the `GRACE_TYPES`, `STEM_DIRECTIONS`, and `DYNAMICS` vocabularies; the validator stays permissive by design.
- **Notation format — standard musical notation as a first-class sloppak type.** Promotes keys, piano, violin, and any other staff-notation instrument out of the guitar wire format and into their own data structure, following the same promotion path used for drums (feedBack#344). New `lib/notation.py` defines the canonical vocabulary (`CLEFS`, `DURATIONS`, `SCHEMA_VERSION`), a permissive `validate_notation()` check, and `measures_to_wire()` / `measure_to_wire()` wire helpers. `lib/sloppak.py::load_song` reads a new per-arrangement `notation:` sub-key from each arrangement entry in the manifest (Option B: per-arrangement, not song-wide), applies path-traversal guards, validates the parsed JSON via `validate_notation()`, and surfaces all notation payloads on `LoadedSloppak.notation_by_id` (a `dict[str, dict]` keyed by arrangement id). A failed or missing notation file for one arrangement does not abort or skip the arrangement itself — partial-failure isolation mirrors the drum tab loader. `file:` is now optional when `notation:` is present: the loader creates a minimal stub arrangement so a notation-only arrangement entry does not require a guitar wire format JSON. `/ws/highway/{filename}` gains two new message types — `notation_info` (staves, instrument, total measure count) and chunked `notation_measures` (32 measures per chunk) — streamed after `sections` and before `anchors`; `song_info` carries a new `has_notation: bool` flag so viz pickers can auto-activate the notation plugin regardless of arrangement name. The notation file schema is measure-structured (`measure → staff → voice → beat → note`), uses MIDI for pitch (no string/fret/tuning indirection), and carries the full set of effects that alphaTab can render. See `docs/sloppak-spec.md` §5.3 for the full schema. Open questions resolved per the piano/keys epic (feedBack#828 / #822): Option B (per-arrangement `notation:` sub-key) and `file:`-optional-when-`notation:`-present are the endorsed design.
- **`song_timeline.json` — beats and sections as a top-level file.** A new optional top-level file pointed at by a new manifest key (`song_timeline: song_timeline.json`) provides the correct home for song-wide beats and sections, replacing the legacy convention of embedding them in the first arrangement JSON. The loader in `lib/sloppak.py` reads and validates the file (must be a dict with `beats` and `sections` as lists), clears and repopulates `Song.beats` / `Song.sections` from it when present, and stores the raw dict on `LoadedSloppak.song_timeline`. The existing arrangement-JSON fallback is fully preserved: all existing sloppaks that omit `song_timeline:` continue to load without any change. This is a prerequisite for notation-only sloppaks, which may have no arrangement JSON at all and therefore no carrier for beats/sections data. New sloppaks should put beats/sections in `song_timeline.json` only. See `docs/sloppak-spec.md` §2 and §5.3.
- **`note-detection` capability domain promoted — control plane (spec 009)** (feedBack#727/#728, epic #828). New core host `static/capabilities/note-detection.js`: provider registry (kinds `midi`/`engine`/`js`, primitives `pitch.estimate`/`verify.target`), requester-owned context-scoped detection bindings (`open-binding`/`close-binding`/`set-target`/`clear-target` — each binding carries its own redacted tuning context, independent of the host's loaded song, per spec-009 FR-003), and hit/miss/verdict observability events (consumers own judgment). The legacy chart-coupled `highway.setNoteStateProvider` surface keeps working and is wrapped for compatibility-shim hit accounting. Diagnostics (`feedBack.note_detection_capability.v1`) carry provider/binding summaries and bounded outcomes — no raw audio, device labels, or song identity. Migrating the chart path, Step Mode verify, minigames YIN, and the engine verifier onto bindings is the remainder of the spec-009 slice.
- **`visualization` capability domain promoted (cap:6)** (feedBack#828). New core host `static/capabilities/visualization.js` registers a provider-coordinator owning the highway renderer surface: commands `inspect` / `list-providers` / `select-renderer` / `clear-renderer` (selection delegates to the existing picker so persistence, WebGL2 gating, and fallback stay single-sourced), events `providers-refreshed` / `renderer-changed` / `renderer-ready` / `renderer-failed`. Legacy discovery (`type: "visualization"` manifests, `window.feedBackViz_*` globals) keeps working unchanged and is accounted as compatibility shims with hit counts. `static/app.js` attributes every renderer change (auto-match / user-select / fallback) and auto-match outcomes into the domain. Diagnostics (`feedBack.visualization_capability.v1`) carry provider ids/labels/context types, active renderer + selection source, last auto-match outcome, and last failure — no song filenames/titles. Per-panel (splitscreen) selection is a tracked follow-up.
- **Viz picker routes notation arrangements** (feedBack#826, epic #828). `window.feedBack.currentSong` gains `hasNotation` (sibling of `hasDrumTab`) from the `song_info` frame's `has_notation` flag, so notation viz plugins (Staff View, Keys Highway 3D) can gate `matchesArrangement` on data presence instead of arrangement-name heuristics. When a notation-only arrangement (no wire notes — `file:` omitted per sloppak-spec §5.3) falls through Auto with no notation plugin installed, the built-in highway still takes the canvas but the Auto label reads "no notation view installed" and a one-shot dismissable hint points at the visualization picker — never a silently blank board.
- **Keys instrument path in progression** (feedBack#828). New `data/progression/paths/keys.json` (5 levels / 15 challenges at parity with the guitar path) plus keys-flavoured daily/weekly quest pool entries (`d.keys-one` "Ivory Tower", `w.keys-three` "Grand Recital"). `lib/progression.py::instrument_for_arrangement()` now attributes `type: piano|keys` arrangements — and names matching `keys`/`piano`/`keyboard`/`synth` on a word boundary — to the new `keys` instrument, so scored keys runs advance the path automatically. Purely content + attribution: no schema or API changes.
- **v3 library: exact artist/album filters + scroll/page-depth restore** (feedBack#857). The v3 Songs toolbar gains Artist and Album dropdowns (Album populates from the selected artist and stays disabled until one is chosen), backed by new exact, case-insensitive (`COLLATE NOCASE`) `artist` / `album` query params threaded through `MetadataDB._build_where` → `query_page` / `query_artists` / `query_stats` and the `/api/library`, `/api/library/artists`, `/api/library/stats` endpoints (the free-text `q` search stays fuzzy and composes with the exact filters). The artist/album catalog is fetched independently of the active artist/album selection so the dropdowns always list the full set for the current provider/search. The toolbar is now sticky so filter controls stay reachable when browsing deep libraries, and returning from the player restores the previous scroll position **and** the loaded infinite-scroll page depth via a `sessionStorage` snapshot keyed by a filter/sort/view state hash (invalidated whenever those change, so a filter change still resets to the top). Tests: `tests/test_library_filters.py` (backend artist/album filters), `tests/js/v3_songs_scroll.test.js` (state-hash + snapshot helpers).

### Fixed
- **The v3 "Up Next" pill can now be turned off — new "Show 'Up Next'" gameplay toggle (default ON).** The v0.3.0 player chrome's persistent upcoming-section pill (`#v3-upnext`, drawn by `static/v3/player-chrome.js`'s `updateUpNext()`) shipped with no off switch, so it always showed during playback whenever a section was upcoming — overlapping the top-right FPS HUD and ignoring the 3D-highway "Show 'Up Next' section card" checkbox (a *different*, in-canvas widget that was demoted to default-off precisely because this pill is the canonical readout). Users reading the pill as the same setting saw "disabled in settings but still there." Adds a real core toggle following the `autoplayExit` idiom: a client-only `showUpNext` `localStorage` pref (absence = enabled), a **Show "Up Next"** switch in the Gameplay settings tab (`static/v3/index.html`), reader/writer + `loadSettings()` hydration + a read-only `window.feedBack.showUpNext` getter in `static/app.js`, and a gate at the top of `updateUpNext()` that hides the pill when off. Disabling mid-playback hides it immediately; re-enabling re-shows it on the next chrome tick (~6 Hz). Added to `RESET_MAP.gameplay.local` in `static/v3/settings.js` so the Gameplay "Reset" restores the default-on state. Default ON = zero change for existing users. No Tailwind rebuild (plain markup + existing classes).
- **v3 list/tree view brought to parity with the grid: select mode, parts chips, and song actions — plus a stale-CSS Docker fix.** Re-lands a previously-reverted change. **Frontend (`static/v3/songs.js`):** entering select mode no longer collapses the tree — `loadTree()` now captures the expanded artist groups (`details[open]` keyed by `data-artist`) before the "Loading…" wipe and restores them on rebuild, so toggling select mode (which re-renders via `reload()`) keeps groups open and selection usable; tree rows gain a display-only checkbox + selection ring, the same fav / save-for-later / overflow-menu cluster as the grid card (always shown, all bound by `wireCards()`), and a capture-phase select guard mirroring the grid so clicking a row or arrangement chip in select mode selects instead of playing (`<summary>` headers sit outside `[data-fn]`, so native expand/collapse is untouched). **Docker fix (`static/tailwind.min.css`):** the committed Tailwind stylesheet was stale — `.sm\:flex` (and the other utilities behind #582's `hidden sm:flex` arrangement chips and the new action cluster) were never compiled in, so they rendered `display:none` on the Docker build (which serves the committed CSS as-is; Desktop rebuilds from source so it looked fine). Regenerated with the pinned `tailwindcss@3.4.19` via `scripts/build-tailwind.sh` so Docker matches Desktop and #582's chips render on every Docker deploy. Regression tests: `tests/browser/v3-tree-select.spec.ts`.
- **Space bar now plays/pauses on the player screen even when a sidebar nav link or rail button has focus.** When any `<button>` in the player rail (viz, audio, mixer, lyrics, plugins, advanced), a sidebar nav link, or a popover control held keyboard focus, pressing Space was swallowed by `_shortcutDispatchBlocked` → `_isInsideInteractiveControl` (which treats `BUTTON`/`A` as interactive), so the Space shortcut never reached the dispatcher and `togglePlay()` never ran. `_shortcutDispatchBlocked` (`static/app.js`) now extends the same carve-out already used for the Section Practice bar: while the player screen is active, Space is always routed through the shortcut system — the dispatcher calls `e.preventDefault()` before invoking the handler, so the focused element does not also activate. Text inputs (`_isTextInput`) remain exempted first, so typing space in a search/input field still works normally, and focus inside a true modal dialog (`role="dialog" aria-modal="true"` / `.feedBack-modal`) layered over the player is also exempted so Space reaches the modal's focused control (e.g. its Close button) instead of toggling playback behind it — non-modal player popovers/toasts (loop A/B, arrangement pin) stay covered. Regression tests in `tests/browser/keyboard-shortcuts.spec.ts` cover the focused-rail-button play/pause, the text-input exemption, and the modal-dialog exemption.
- **A song's accuracy badge now updates on its library card right after you play it — no restart needed.** The v3 library (`static/v3/songs.js`) loaded the best-accuracy map (`/api/stats/best`) once into `state.accuracy` at render time and only ever refreshed it on a full re-render; the play→return flow takes the screen-entry fast-path that restores the cached grid DOM without re-fetching, so a just-earned score stayed invisible until the next restart re-ran `render()`. The `stats-recorder` now emits a `stats:recorded` event (carrying `filename`/`arrangement`) once the scored `POST /api/stats` resolves on the server — the correct moment, since `song:stop` fires before the POST completes. `songs.js` listens: if the library is the active screen it re-fetches `/api/stats/best` and patches the affected card/row badge in place; otherwise it marks the filename dirty and `onV3SongsScreenEnter` applies it on return (a failed fetch keeps the entry dirty to retry). Badge markup was factored into a shared `accuracyBadge(filename, variant)` (grid pill + tree-row percentage, both tagged `.fb-acc-badge`) so the in-place `repaintAccuracy` can find and replace them without a full list re-render (scroll/pagination preserved). The old empty `song:stop` "refresh lazily next render" placeholder is replaced.
- **Changing Settings → 3D Highway → Fret spacing no longer ejects you to the home screen.** The `highway_3d` plugin's `h3dSetFretSpacing` was the lone 3D-highway setting that called `location.reload()` to apply — and since the SPA boots with `#home` as the active screen (`index.html` `.screen.active`), the reload dropped the user out of Settings onto the homescreen. It now applies live like every other 3D-highway setting: it rebinds the module-scope `_h3dFretUniform` flag (so panels mounted later this session pick up the new mode), recomputes the two `fretX`-derived scalars that were baked at init (`_fretLabelScaleRefW` for fret-label sprite scaling, `FRET_WIDTH_MID` for camera hysteresis), and broadcasts a `fretSpacing` change over the existing `_bgEmitChange` pub-sub so every mounted panel rebuilds its board via `buildBoard()`. Per-frame note geometry already reads `fretX` live and needs no rebuild. No page reload, so the Settings screen stays put. Source-level regression tests in `tests/js/highway_3d_fret_spacing.test.js` now pin the no-reload / live-rebuild behavior.
- **v3 library scroll-restore no longer breaks the classic v2 UI or drops off-screen searches** (feedBack#857). Two regressions in the scroll-restore work above: (1) `playSong` remapped `home`-launched songs to return to the `#v3-songs` screen unconditionally, but `static/app.js` is shared with the v2 UI (served at `/v2` / `FEEDBACK_UI=v2`) where that screen does not exist — Esc-from-player then called `showScreen('v3-songs')`, which threw on the missing element and stranded the user on a blank screen with playback still running; the remap now applies only when `#v3-songs` is present. (2) The Songs screen-entry fast-path skips reloading to preserve scroll, but the global topbar search routed through it, so once Songs had been visited, searching from another screen navigated there without applying the new query; the screen now tracks the state hash each fetch reflects and refetches when it has drifted, keeping the scroll-preserving no-op only when nothing changed.
- **An active custom highway renderer is no longer starved of `draw()` when it hides the canvas** (#819). The per-frame draw gate in `static/highway.js` bailed on `if (!_lastVisible) return`, which conflated two different "hidden" states: a genuine off-screen canvas (`offsetParent === null` — navigate-away / `display:none` splitscreen panel, #246) versus a renderer-set *override-hide* (`setVisible(false)`, where an opaque overlay covers the canvas but the active renderer keeps painting its own surface). The gate now only pauses everything for the off-screen case (and still pauses the default 2D renderer on an override-hide); the **active custom renderer** keeps receiving `draw()` through its own override-hide. The `highway:visibility` event still fires before the gate, so sibling overlay renderers (e.g. 3D Highway's `.h3d-wrap`) still pause. This is the core-side root cause behind the Tab View cursor freezing in single-player (feedBack#734; worked around plugin-side in feedBack-plugin-tabview#25).
- **Screensaver no longer kicks in during windowed-mode playback** (#686). While a song is playing, `static/app.js` now holds a [Screen Wake Lock](https://developer.mozilla.org/en-US/docs/Web/API/Screen_Wake_Lock_API) (`navigator.wakeLock.request('screen')`) so the OS display/screensaver stays awake even though only audio + the highway animation are active and the keyboard/mouse are idle. The lock is acquired on `song:play`/`song:resume` and released on `song:pause`/`song:ended`/`song:stop` (kept only while actually playing), and re-acquired on `visibilitychange` when the tab refocuses (the API auto-releases a lock whenever the page is hidden). Both the HTML5 `<audio>` and JUCE desktop playback paths emit the same `song:*` events, so the fix covers both. In feedBack-desktop (Electron), where `navigator.wakeLock` is unreliable, it also drives a native `powerSaveBlocker` bridge via the optional `window.feedBackDesktop.power.setScreenAwake` hook when present; both calls degrade silently where unsupported. Note: the browser Wake Lock API is secure-context only, so in a plain browser this is active on `localhost` / HTTPS only — a session opened over plain HTTP to a LAN IP (e.g. `http://192.168.1.100:8000`) won't keep the screen awake; front it with HTTPS or use the desktop app (see README → reverse-proxy notes).

### Changed
- **Practice plugin first-class sidebar slot now points at Virtuoso.** The bundled practice plugin was rebranded/re-homed from the SlopScale fork (`id: slopscale`) to `got-feedback/feedBack-plugin-virtuoso` (`id: virtuoso`); the desktop bundle swap is feedBack-desktop#31. `static/v3/shell.js` still promoted `slopscale`, whose id no longer ships — so `renderPromotedNav()` (gated on the plugin appearing in `/api/plugins`) would have found no match and the dedicated sidebar slot would have gone dark, dropping Virtuoso to the generic Plugins gallery. Update the NAV entry + `PROMOTED_PLUGINS` slot `slopscale` → `virtuoso` (`screen: plugin-virtuoso`, label "Virtuoso - Practice", same FeedBarcade anchor + `target` icon) so the practice plugin keeps its first-class entry. Also clear the now-dead `slopscale` id from the Plugins-gallery curated category map (`static/v3/plugins-page.js`) and add `virtuoso: 'practice'` as a defensive fallback (the manifest's `category: "practice"` is authoritative, so it lands on the practice board regardless), and refresh the stale SlopScale references in `README.md` + `docs/plugin-capability-inventory.md`. Must land with the bundle swap or the practice plugin regresses in the UI.
- **3D highway: realistic curved metal frets.** The fret wires are now bowed `TubeGeometry` (the middle strings push away from the camera so the row of frets reads as wrapping a cylindrical neck — a depth cue) rendered with a lit `MeshStandardMaterial` instead of the old flat, straight `MeshBasicMaterial` boxes, so the scene's ambient + directional light glints across the rounded surface for a polished-steel look. The existing per-frame highlight is preserved unchanged: frets inside the active anchor still turn gold (`0xD8A636`), which under the metallic shading reads as brass. Metalness is kept moderate (0.4, not full-metal) because the scene has no envMap — a PBR full-metal surface would reflect black — with a dim emissive floor so frets stay legible down the fogged neck. Backported from the `highway_babylon` plugin's "hit-zone fret bars". All knobs (`FRET_BOW_DZ`, metalness/roughness/emissive) are tunable constants. `plugins/highway_3d` v3.25.0.
- **3D highway: section + tone HUD cards now default OFF.** The v0.3.0 player chrome carries a persistent "Up Next" pill, making the in-canvas section card redundant by default (it doubled the readout, feedBack feedback); the tone HUD follows the same less-is-more default. Both remain available in Settings → 3D Highway (visibility/position/size unchanged); users who previously toggled either explicitly keep their stored preference — only the untouched default flips. `plugins/highway_3d` v3.24.1.
- **Perf**: replace runtime Tailwind Play CDN with a prebuilt static stylesheet (`static/tailwind.min.css`). The Play CDN's runtime JIT scanned the DOM ~1.8x/sec on the main thread (~37 ms blocking spans), dropping ~26% of frames in long playback sessions with the 3D highway as default. Theme extensions (dark/accent/gold colors, Inter font) move to `tailwind.config.js`; regen via `bash scripts/build-tailwind.sh`. No runtime build step — the generated CSS is committed. Fixes feedBack-desktop#110.
- **Perf**: reduce per-frame allocations in the 2D highway chord + lyric render paths. `_ensureChordRenderCache` now also caches `sortedNotes` / `nonZeroNotes` / `nonZeroFrets` / `allMuted` / `hasMultipleNotes` (computed once per chord, invalidated on `src` / `_inverted` / `chordTemplates` change — the third key catches a stale `isOpen`-derived classification when the WS `chord_templates` message lands after the final `chords` chunk), so `drawChords` no longer re-sorts / re-filters / spreads min-max per visible chord per frame. The in-chord unison bend classification is folded inline (no `chordPositions.filter` × 2 per frame). `drawLyrics` memoizes `ctx.measureText` results in a two-level `Map<fontSize, Map<text, width>>` so cache hits don't allocate a composite string key. Lit-sustain shimmer in `drawSustains` swaps the 4 per-note-per-frame `Math.random()` calls for a 64-entry precomputed jitter LUT (xorshift32-seeded — the LUT contents are reload-stable and test-reproducible; rendered shimmer is deterministic per `createHighway()` instance, since the seed includes that instance's `_frameIdx`) indexed by `(frameIdx + n.s + ⌊n.t·60⌋)`, visually indistinguishable and allocation-free.

### Removed
- **`c` library hotkey ("Convert to .sloppak") removed from core.** Core hardcoded a plugin-specific shortcut: a documentation-only `registerShortcut({ key: 'c', scope: 'library' })` no-op plus a `c → button.sloppak-convert-btn` entry in the library keydown handler that fired the Sloppak Converter plugin's button. Per the plugins-own-their-behavior principle, core no longer ships this hotkey — the convert button still works by click, and the Sloppak Converter plugin can register its own `c` shortcut via `window.registerShortcut()` if keyboard access is wanted. The `f` (favorite) and `e` (edit) library hotkeys, which drive core buttons, are unchanged. Help-modal/registry tests in `tests/browser/keyboard-shortcuts.spec.ts` updated to drop the `c` assertions.

### Added
- **Player progression: Mastery Rank, instrument-path challenges, daily/weekly quests, Decibels currency, cosmetics shop (spec 010).** Onboarding gains two steps: pick one or more **instrument paths** (Guitar / Bass / Drums — data-driven, more can ship as content) and a **calibration challenge** offer (play the bundled FeedBack Diagnostic with note detection at 100% accuracy — or skip; either way you reach **Mastery Rank 1**, and a skipped calibration can still be completed later from the Progress screen). Each path levels by completing a content-defined number of **challenges** (any order) from that level's set; Mastery Rank = onboarding rank + the sum of path levels, starting at 0 on a fresh install. The existing unified XP backend is untouched but the frontend renames it to **Decibels (dB)** — a spendable currency earned ONLY by playing (songs, FeedBarcade rounds, quest rewards; no real-money path exists or may be added) — with spend tracked in a separate wallet so lifetime earnings stay monotonic. Rotating **daily/weekly quests** (deterministic per period, lazy instantiation, local-midnight / Monday resets) award dB and feed `quest_completed` challenges. A new **Progress** screen (rank hero, per-path checklists, quest countdowns, add-a-path) and **Shop** screen (themes via CSS-variable swaps under `html[data-fb-theme]`, avatar frames; atomic balance-checked purchases — 402 on insufficient dB, 409 on re-buy) join the v3 nav, and the topbar badge now shows Rank + challenge-set progress + dB balance. All definitions live in `data/progression/` JSON (paths/levels/challenges, quest pools, shop catalog) — adding a rank, challenge, quest, or cosmetic is a content edit + restart, never code; invalid content degrades to logged warnings. New tables (additive + idempotent): `progression_state`, `player_paths`, `challenge_progress`, `quest_state`, `wallet`, `shop_owned`, `shop_equipped`. New endpoints: `GET /api/progression`, `POST /api/progression/paths|onboarding|events` (events whitelists `minigame_run`; `song_completed` stays server-derived inside `POST /api/stats`, which now resolves the instrument server-side and reports an additive `progression` outcome key), `GET /api/shop`, `POST /api/shop/buy|equip`; equipped cosmetics ride along on `GET /api/profile`. A new **`progression` capability domain** (core-owned, kind: command, safety: safe — `inspect`, `record-event`, `list-shop`, `buy-item`/`equip-item` gated on user action) emits `challenge-completed`/`quest-completed`/`path-level-up`/`rank-changed`/`db-changed`/`calibration-completed`/`cosmetic-equipped`, mirrored as `progression:*` window events, with a redaction-safe diagnostics contributor; backend plugins get the symmetric `record_progression_event` context hook (the bundled minigames hub reports runs through it, guarded for standalone). Spec: `specs/010-progression-domain/`. Tests: `tests/test_progression.py`, `tests/test_progression_api.py`. **Migration notes:** existing XP totals carry over as lifetime dB (balance = lifetime − spent); resetting a per-source XP contribution (e.g. a minigames profile reset) after spending can clamp the spendable balance to 0 until new dB is earned; drums-path v1 content uses currently-satisfiable goals (arcade rounds, quests, any-instrument plays) until drums scoring lands.
- **3D highway score FX (notedetect game-scoring layer).** The bundled `highway_3d` renderer now visualizes the scoring layer shipped in feedBack-plugin-notedetect ≥1.13: floating **"+N" score pops** above each judged gem (sourced from the note-state provider's new `{ points, mult, popKey }` verdict fields — chord members share the chord-level `popKey`, so a chord pops once, not once per string), plus session-level FX from the new `notedetect:fx` event — a particle burst at the strike line on streak milestones (25/50/every 100), an expanding ring pulse on multiplier tier-ups (×2/×3/×4), and a brief red wash when a ≥10 streak breaks. Colors and the pop font follow the user's notedetect scoring-UI skin (`feedBack_notedetect_skin`: neon/esports/metal, refreshed live on the `notedetect:skin` bus event). Everything renders on the existing 2D overlay canvas from fixed-size slot pools — no Three.js geometry, no text-sprite cache traffic, near-zero cost when idle — and degrades to a silent no-op with older notedetect builds (the new fields/events simply never arrive). Splitscreen panels scope FX to their own detector instance via the bubbling per-panel `notedetect:fx` dispatch. `plugins/highway_3d` v3.24.1.
- **3D highway: slide direction arrows + gem-follow animation.** Slide notes now show a ›/‹ arrow indicating which way the slide goes — on the note/gem itself, as an early preview on the neck before the note arrives, and (optionally) chained further ahead for multi-leg slides — each independently toggleable in Settings → 3D Highway (`slideArrowApproachVisible`, `slideArrowNeckVisible`, `slideArrowChainPreviewVisible`). The note gem also now visually glides from its starting fret to the slide's destination over the note's sustain and holds there through the brief post-sustain linger, instead of snapping back to the starting fret — most noticeable on unpitched "slide to nothing" notes. `plugins/highway_3d` v3.25.2.
- **3D highway: up to 3 upcoming-note ghost previews per string, with fade-in/grow.** Each string now previews up to 3 upcoming notes (was 1) on a fixed 0.6 s fade-in/grow ramp, so tight same-string runs no longer pop in at full size right before impact and the player can read note order ahead of time. `isBlocked` (the pre-impact ghost suppression in a note's last 150 ms) is now scoped to chord notes only — for lead notes it had been blinking the ghost out right before each sustained note in dense runs. (Slide notes stay excluded too, per the slide-arrow work above, since their gem glides off the start fret.) `plugins/highway_3d` v3.26.0.
- **Enable/disable plugins from the v3 Pedalboard (footswitch backend).** Every `/api/plugins` entry now carries an `enabled` boolean (default `true`), and a new `POST /api/plugins/{plugin_id}/enabled` endpoint (`{"enabled": <bool>}` → `{"id", "enabled"}`) persists the choice to `CONFIG_DIR/plugin_state.json` (only non-default `enabled:false` entries are stored; a missing/corrupt file is tolerated and never crashes startup). The loader **skips disabled plugins at startup** — no requirements install, no `routes.setup()`, no screen/nav/capabilities — while still surfacing them in `/api/plugins` as a disabled entry (`status:"disabled"`, `enabled:false`) so the UI can show an "off" pedal you can switch back on. Toggling persists immediately and flips the in-memory flag so the next `/api/plugins` reflects it at once (a runtime-disabled plugin's already-mounted routes/screen remain until the next restart; re-enabling a startup-skipped plugin mounts on restart). A disabled plugin is **excluded from the capability pipeline** — its capability metadata is emptied in `/api/plugins`. Guard rails keep `capability_inspector` and `app_tour_*` always enabled (disable → `400`); unknown id → `404`; missing/non-boolean `enabled` → `400`. Backend only; the v3 Pedalboard frontend consumes this contract. Docs: `docs/plugin-v3-ui.md`.
- **fee[dB]ack v0.3.0 rebrand + UI redesign (opt-in, isolated).** The visible product is being renamed from **FeedBack** to **fee[dB]ack** (the `[dB]` is a decibel pun on the practice "feedback" loop) alongside a full dashboard-style UI redesign. **Rebrand scope is the app + docs wordmark only** — the repository, Python package, ghcr Docker image, `CONFIG_DIR`, and `FEEDBACK_*` env vars all keep the `feedBack` name, so existing deployments and data are unaffected. The redesigned UI is additive and served behind a feature flag: `FEEDBACK_UI=v3` flips the `/` route to the new `static/v3/` shell, and `GET /v3` always serves it; the default `/` stays byte-identical to 0.2.9 until 0.3.0 flips the default. This release adds the `static/v3/` scaffold (navy app shell + styled fee[dB]ack wordmark, brand SVG + favicon + PWA manifest with 192/512 icons), an additive `fb` Tailwind color palette (legacy `dark`/`accent`/`gold` retained) with `static/v3/**` in the content globs, and the regenerated `static/tailwind.min.css`. Vanilla JS, prebuilt Tailwind, no Play CDN (Principle II). Shell wiring, screens, profile/scoring backends, and capability-runtime integration land in subsequent v0.3.0 changes.
- **fee[dB]ack v0.3.0 app shell (sidebar + topbar + routing).** The v3 shell (`static/v3/index.html`) is now a re-chromed copy of the legacy app: the new left **sidebar** (HOME / LIBRARY groups) and **topbar** (secondary nav, search, Support, badge-cluster mount points) replace the hidden legacy navbar, and new `#v3-*` screens (dashboard/plugins/profile/playlists/saved) are added — while all legacy screens (`#home` library, `#favorites`, `#settings`, `#player`, `#audio`, plugin nav containers) are kept verbatim so `static/app.js` boots **unmodified** and the whole engine (player/highway, plugin loader, capabilities, audio, library, settings) is reused as-is. Navigation is the shared `window.showScreen` across `#v3-*`, reused legacy, and `#plugin-*` screens, with a responsive hamburger and a `localStorage`/`v3:`-namespaced shell. Plugin nav is mirrored into the sidebar from `/api/plugins` (UI placement is a deferred capability domain, so this uses the legacy loader, not capability dispatch). `static/v3/shell.js` wraps `window.showScreen` via the idempotent rehydration pattern to keep sidebar/topbar active-state in sync.
- **fee[dB]ack v0.3.0 player profile + first-run onboarding + unified XP + streak.** Adds a single-user core **profile** (`profile`/`profile_progress`/`xp_profile` tables in `web_library.db`, additive + idempotent): display name + avatar, a stable `player_hash` (SHA-256 of the first name + a once-generated salt — stable across later renames; a future-leaderboard label, never auth), and a **streak** (any session on a calendar day keeps it; a missed day resets to 1). New endpoints: `GET/POST /api/profile`, `POST /api/profile/avatar` (base64, re-encoded to a ≤512px PNG under `CONFIG_DIR/avatars/`), `GET /api/profile/avatar/{name}` (safe-joined), `GET /api/profile/avatars` (bundled defaults under `static/v3/avatars/`), `GET /api/profile/progress` (one call for the badge), and `POST /api/xp/award`. **Unified XP:** `lib/xp.py` is the single XP curve (same math the minigames plugin shipped); the core `xp_profile` store is the one source of truth the profile badge reads, exposed to plugins via `context["award_xp"]`/`get_xp_progress`/`seed_xp`. The bundled **minigames** plugin now delegates XP to the core store (seeding once from its existing `profile.json` so earned levels carry over) — so song-play, minigames, and tutorials all feed one level. Frontend: a blocking first-run onboarding overlay (name + avatar grid + upload), the topbar profile badge (avatar, 🔥 streak, level + XP bar), and the `#v3-profile` screen. Tests: `tests/test_xp.py`, `tests/test_profile_api.py`.
- **fee[dB]ack v0.3.0 song-stats store (best score + accuracy, plays, resume position).** A core `song_stats` table (`web_library.db`, additive + idempotent, PK `(filename, arrangement)`) records per-song/arrangement best/last score + accuracy, play count, and last position. Endpoints: `POST /api/stats` (scored session → `plays += 1`, `best_*` = max, `last_*` = new, plus **unified-XP award** `xp_for_run(score)` and a **streak** bump, both behind try/except so a side-effect failure never drops the stat write; or position-only `lastPlayPosition` → resume touch with no `plays` change), `GET /api/stats/{filename}` (aggregated across arrangements), `GET /api/stats/recent` (joined to song title/artist/art for "Jump back in"). Scoring stays frontend-driven: `static/v3/stats-recorder.js` tallies the `note:hit`/`note:miss` events the optional `feedBack-plugin-notedetect` already emits (and also accepts an explicit `note_detect:session-ended` summary), then POSTs on song end; it also persists resume position on pause/stop. No note-detect edit required — note-detection is a deferred capability domain, so the recorder uses those legacy events and degrades to "no accuracy" when the plugin isn't installed. Score/accuracy math is shared with the server via `lib/song_score.py`. Tests: `tests/test_song_score.py`, `tests/test_song_stats_api.py`.
- **fee[dB]ack v0.3.0 playlists, Saved for Later, and Continue-Playing.** Core playlist management (`playlists` + `playlist_songs` tables in `web_library.db`, additive + idempotent): create/rename/delete, add/remove/reorder songs, plus a reserved **Saved for Later** system playlist (created on first use; protected from rename/delete). Endpoints: `GET/POST /api/playlists`, `GET/PATCH/DELETE /api/playlists/{id}`, `POST /api/playlists/{id}/songs`, `DELETE /api/playlists/{id}/songs/{filename}`, `POST /api/playlists/{id}/reorder`, `POST /api/saved/toggle`, and `GET /api/session/continue` (derives the resume song + last position from `song_stats`, no new table). Frontend `static/v3/playlists.js` renders the `#v3-playlists` list + detail (drag-reorder, play, remove) and `#v3-saved`, and exposes `window.v3Saved.toggle()` for a "Save for later" affordance on song cards. Favorites reuse the existing favorites screen/API. Core REST, no capability domain. Tests: `tests/test_playlists_api.py`.
- **fee[dB]ack v0.3.0 Dashboard / Home.** The `#v3-home` dashboard (matching the v0.3.0 design target) composes the new backends: a "Welcome back, {name}!" banner with a patch-notes link (`/api/version`), a hero card (Start Playing / Create Lobby), a **Continue-Playing** card (`/api/session/continue` → art, tuning chip, 4-segment progress; click resumes via `playSong` + best-effort seek), a stats row (audio-routing widget placeholder until prompt 18, library count from `/api/library/stats`, plugins count from `/api/plugins` where `status==="ready"`), and a **Recently Played** grid (`/api/stats/recent`) with per-song accuracy badges (good/mid/low ramp). Each widget fetches + renders independently and degrades gracefully (missing/empty endpoint → placeholder, never blocks first paint). `static/v3/dashboard.js`; re-renders on return to Home and on profile update.
- **fee[dB]ack v0.3.0 tuner + instrument topbar badges.** The topbar gains an **instrument selector** (guitar/bass + string count + tuning + reference pitch) persisted via additive `/api/settings` fields (`reference_pitch` clamped 430–450, `instrument`, `string_count` 4–8, `tuning` name or semitone offsets); changing it emits `instrument:changed` so the note_detect scorer can re-tune (consumed once the external plugin adopts it). A **live tuner badge** stays idle until the user enables the mic (explicit gesture; `getUserMedia`), then shows a YIN note readout with a cents needle (green within ±5¢) using a new dependency-free `static/v3/tuner-core.js` (YIN + frequency→note/cents, honoring the reference pitch); clicking opens the full `feedBack-plugin-tuner` screen when installed. CPU-friendly (~20 Hz, paused when the tab is hidden, respects `prefers-reduced-motion`). Tests: `tests/test_settings_instrument.py`, `tests/js/tuner_core.test.js`.
- **fee[dB]ack v0.3.0 audio-routing widget (dashboard).** The dashboard's audio stat tile now reads the live audio session **through the capability runtime** — `audio-mix inspect` (route + faders + required kinds), `audio-input list-sources` (selected/available input), `audio-monitoring inspect` — and renders **Audio Input → VST/NAM/IR → Audio Output** with per-node state dots and a Connected/Not Connected line. It never touches `audio-mixer.js` internals or `nam_tone` routes directly; "Not Connected" is the honest browser default (no native route), and it degrades on `no-owner`/`no-handler`/`failed` or absent capabilities. Refreshes on `instrument:changed`, play/stop, capability audio events, and each Home visit. `static/v3/audio-routing.js`.
- **fee[dB]ack v0.3.0 Plugins page.** The `#v3-plugins` screen renders the enriched `/api/plugins`: a "{N} active" header (`status==="ready"`), a card grid per plugin (icon, name, version, status pill with the error on failed, capability summary badges — declared domains / validation warnings / unsupported versions / shim hits / bundled / type), an **Open →** action that navigates to the plugin's injected `#plugin-<id>` screen, and All/Bundled/Visualizations filters. Surfaces a deep-link to the bundled **Capability Inspector** rather than re-implementing the graph. No new backend. `static/v3/plugins-page.js`.
- **fee[dB]ack v0.3.0 Songs / Library screen (`#v3-songs`).** A native vanilla-JS library browser over the existing `/api/library*` endpoints: provider selector (via the `library` capability, not DOM scraping), grid + tree views, sort, format filter, a tri-state filter drawer (arrangements / stems / lyrics / tunings), topbar-driven search (debounced), infinite scroll, fb song cards with **accuracy badges** (good/mid/low ramp, batched via a new `GET /api/stats/best`), favorite + save-for-later affordances, and upload (reuses the existing uploader). The "Songs" sidebar nav now opens this screen. No regression to `/api/library*`. `static/v3/songs.js`.
- **`ui.library-card-injection` capability + native song-card actions (fee[dB]ack v0.3.0).** New core capability (`static/capabilities/library-card-actions.js`, owner `core.ui.library-card-injection`, exposed as `window.feedBack.libraryCardActions`) lets plugins **register** per-song library-card actions (id, label, placement, applicability, enabled state, run handler) with `action-registered`/`action-result` events — replacing the legacy `.song-card` DOM-injection pattern (roadmap domain #9, now delivered as a frontend host). The native Songs grid renders registered actions in each card's "⋮" menu; the built-in **Edit metadata** and **Convert to E Standard (retune)** actions ship through it (`static/v3/card-actions-core.js`, calling the existing `openEditModal`/`retuneSong` globals). Songs cards also gain **arrangement chips** (play a specific arrangement) and a **multi-select** mode with batch **Add to playlist** / **Save for Later**. Recipe in `docs/capability-recipes.md`; tests in `tests/js/library_card_actions.test.js`. Migrating the external card-action plugins (Sloppak Converter, Find More, editor) onto `register(...)` is a follow-up.
- **`centOffset` exposed via `getSongInfo()`** — the arrangement `<centOffset>` field (float, cents) is now parsed from all chart sources (loose folder XML, sloppak wire format) and sent as `centOffset` in the `song_info` WebSocket message. Plugins can read `getSongInfo().centOffset` to obtain the arrangement's pitch-shift offset — commonly `-1200.0` for extended-range bass (one octave down) or a small non-zero value for true-tuned content (e.g. A443 ≈ +11.8 cents). Defaults to `0.0` when absent.
- **`highway.getPhrases()` and `highway.getMastery()` public plugin API** — exposes phrase timing windows (`[{ index, start_time, end_time, max_difficulty }]`) and the current mastery slider value (`0..1`) as documented, stable plugin API. Both values were already in memory and reachable via internal names; this surfaces them with intent so plugins can implement section-aware logic (e.g. tracking accuracy per phrase, suppressing difficulty changes during a hard solo) without reaching into undocumented internals. Returns `null` when the song has no phrase data (GP imports, single-difficulty charts). Pair with the existing `hasPhraseData()` to gate phrase-aware code paths.
- **Tailwind freshness guard + wider plugin scan.** A new `tailwind-fresh` CI job (`.github/workflows/tests.yml`) rebuilds `static/tailwind.min.css` with the pinned `tailwindcss@3.4.19` and hard-fails on any diff, so the committed prebuilt stylesheet can no longer silently lag source (after PR #411 removed the runtime Play CDN, a stale file shipped unstyled elements with no guard). The `tailwind.config.js` plugin content glob is widened to `./plugins/**/*.{js,html}`, which also scans non-`screen.js` plugin JS (e.g. `plugins/app_tour_*/script.js`) that was previously invisible to the build. Regenerating under the wider glob is a no-op for runtime behaviour — it only adds classes that were already used in source. Groundwork for the plugin `styles` capability (constitution 1.1.0, Principle II): runtime-installed plugins ship their own compiled CSS rather than relying on core's build-time scan.
- **Plugin capability pipelines** — adds the first versioned capability coordination layer for plugin authors and support tooling. `/api/plugins` now exposes validated capability declarations, validation warnings, unsupported-version metadata, UI/runtime domain declarations, and compatibility shim summaries for legacy `nav` / `screen` / `settings` / `routes` / visualization surfaces. The browser runtime now tracks manifest participants separately from live handlers, explicit dispatch outcomes (`no-owner`, `no-handler`, `unsupported-command`, `incompatible-version`), claim lifecycle cleanup, manual override precedence, deterministic ownership conflicts, multi-provider ordering, shim hit counts, and a redaction-safe diagnostics snapshot capped at 64 KB. A bundled Capability Inspector plugin shows the live graph, and new docs cover the manifest schema, recipes, safety matrix, lifecycle cleanup, and diagnostics contract.
- **Audio graph/session capability slice** — promotes `audio-mix`, `audio-input`, `audio-monitoring`, and coordinated `stems` diagnostics into the capability runtime. The new audio session host records song route/fader state, redaction-safe input sources, monitoring lifecycle outcomes, stem automation claims/overrides/orphans, and compatibility bridge hits for legacy faders, song volume, Stems master volume, 3D Highway analyser taps, audio startup barriers, and input source handoffs. `core.audio.session` coordinates `stems` without replacing the Stems plugin as the owner of actual stem playback/state.
- **Audio-mix control plane** — makes `audio-mix` the player mixer source of truth. Core now exposes `list-faders`, `get-fader-value`, `set-fader-value`, `inspect-route`, and `inspect-analyser` through the capability runtime, routes native and compatibility-backed fader provider operations with a 2-second timeout, reports committed values back to the mixer UI, suppresses matching legacy faders when a native participant owns the same logical control, and expands audio-session diagnostics/Capability Inspector rendering for fader availability, source modes, bridge hits, route/analyser summaries, and timeout failures.
- **Audio-input control plane** — makes `audio-input` the redaction-safe source of truth for instrument input discovery and lifecycle. Core now exposes `list-sources`, `select-source`, `open-source`, and `close-source` through the capability runtime, persists selected logical sources, keeps inspect/list/select prompt-free, routes provider `source.open`/`source.close` operations with bounded outcomes, shares compatible open sessions across requesters, suppresses compatibility-backed duplicate sources when a native provider owns the same logical key, and expands audio-session diagnostics/Capability Inspector rendering for selected input, open sessions, bridge hits, storage status, and permission/device failures without exposing raw device labels or live audio handles.
- **Audio-monitoring control plane** — makes `audio-monitoring` the shared live-monitoring coordinator. Core now exposes provider registration/list/selection, explicit user-action `start`, requester-counted `stop`, prompt-free `inspect`/`monitoring.status`, and `set-direct-monitor` through the capability runtime. Monitoring starts integrate with selected `audio-input` readiness, background requesters can only attach to active compatible sessions, active sessions survive song/playback stops without auto-resuming after reload, native providers suppress compatibility-backed legacy monitor paths, and diagnostics/Capability Inspector now show providers, sessions, requesters, direct-monitor state, bridge hits, and distinct safe outcomes (`provider-selection-required`, `user-action-required`, `incompatible`, `unavailable`, `stopped`, etc.) without exposing raw audio/device data.
- **Playback control plane** — promotes `playback` to an active core capability domain for song transport, timing, loop, route, requester/observer, bridge, and diagnostics state. Core now exposes `inspect`, user-authorized `start`, `pause`, `resume`, `stop`, `seek`, `set-loop`, and `clear-loop` through the capability runtime while `static/app.js` keeps raw `<audio>`/JUCE handles private behind a redaction-safe adapter. Playback diagnostics use pseudonymous targets in exported bundles, local display labels only in the Capability Inspector, bounded recent outcomes/events, and bridge accounting for `window.playSong`, legacy `song:*` events, `window.feedBack` transport helpers, loop helpers, and browser/native route handoff.
- **3D highway — Tone HUD, fret dividers, chord-diagram toggle, FPS counter.** The bundled `plugins/highway_3d` gains an amber **Tone-change HUD** (shows the active tone and the next scheduled tone change; position / size / visibility configurable in settings), a **fret-dividers** toggle (vertical dividers on the highway, on by default, via `h3dBgSetFretDividersVisible`), a **chord-diagram visibility** toggle (`h3dBgSetChordDiagramVisible`), and an **FPS counter** setting migrated to `BG_DEFAULTS.fpsVisible` (drops the legacy `h3d_showFps` localStorage key). Chord-diagram position is restricted to `tl`/`tr`; legacy `bl`/`br` values are coerced on load. Perf: accent-halo shell descriptors are pre-built per string in `initScene()` and the chord-verdict cache key is encoded as a number, eliminating per-frame allocations in the `drawNote()` and chord hot paths.
- **Sloppak assembly preserves a short preview clip.** When a source chart carries a separate short browser-preview audio clip alongside the full song, the sloppak assembler now decodes it to `preview.ogg` at the sloppak root and records it under a new top-level `preview:` manifest key (POSIX relpath, same shape as `lyrics`/`cover`). A failed preview decode is logged at debug and skipped without aborting the overall build. Sources with no separate preview are unaffected. Older sloppak readers ignore the unknown `preview` key, so the change is purely additive (sloppak-spec.md §5.5 backward-compat). Documented in `docs/sloppak-spec.md` §2 alongside the other optional top-level keys. Enables [`feedBack-plugin-song-preview`](https://github.com/got-feedback/feedBack-plugin-song-preview) to render hover-to-listen previews for sloppaks without seeking into the full audio.
- **Generic plugin asset route** — `GET /api/plugins/{plugin_id}/assets/{path}` serves arbitrary static files a plugin bundles under its own `assets/` directory (AudioWorklet modules, WASM, images, etc.), so plugins can self-host browser-fetchable assets without a CDN (Principle II). Containment is enforced by `lib/safepath.safe_join` against `<plugin>/assets/`, so `..` traversal, absolute paths, and NUL bytes cannot escape `assets/` to reach a plugin's Python modules. `.js` is served as `application/javascript`. First consumer: the stems plugin's pitch-preserving time-stretch worklet.
- **Minigames framework — bundled as a core plugin (`plugins/minigames/`).** Promotes the upstream [`feedBack-plugin-minigames`](https://github.com/got-feedback/feedBack-plugin-minigames) repo into the core bundle so every FeedBack install gets the framework out of the box (same promotion path used for `highway_3d`). The plugin adds a top-level **Minigames** nav link (alongside Library / Favorites / Upload — not buried in the Plugins dropdown), a library-style card grid of installed minigame plugins, and a shared profile layer (XP, level, per-game leaderboards, cross-minigame unlocks) persisted under `CONFIG_DIR/minigames/` and opted into the settings export. Other plugins that want to ship a minigame add a `minigame` block to their `plugin.json` and call `window.feedBackMinigames.register(spec)`; the SDK exposes scoring (`createContinuous` runs a self-contained YIN tracker; `createDiscrete` / `createChord` wrap `note_detect`'s `createNoteDetector`), HUD primitives, run persistence, and a scheduler so individual minigames don't need their own DSP or backend. Backend endpoints live under `/api/plugins/minigames/{runs,profile,registry}`. The framework is plugin-shaped (not core code) per Principle III, but bundled so it ships with every install. First consumer: [`feedBack-plugin-flappy-bend`](https://github.com/got-feedback/feedBack-plugin-flappy-bend), shipped separately.
- **Alpha-build heads-up banner** — when `/api/version` reports a version string containing "alpha" (case-insensitive), an amber banner appears at the top of the library section warning users that the build is in active development and may have bugs or breaking changes. The banner stays hidden on stable / beta / RC builds. No persistence or dismiss state — it's a passive notice, not a modal.
- **Drum vocabulary expanded to 18 pieces** — adds `stack` (MIDI 30, from GM's extended-percussion range, unused by real drum-kit MIDIs) and `bell` (MIDI 80 "Mute Triangle", also unused in real drum-kit MIDIs) to `lib/drums.py` PIECES. Inserted in the iteration order so the editor / highway lane ordering is *hi-hat → stack → crash → … → ride bell → bell*. Both are cymbals; default shape `circle_jagged` (stack) / `circle_dot` (bell). Old drum tabs round-trip unchanged — the schema is permissive and existing piece-ids are untouched.
- **GP / MIDI drum import surfaces unmapped notes** — `convert_drum_track_to_drumtab` (`lib/gp2rs.py`) and `convert_drum_track_from_midi` (`lib/midi_import.py`) gain an optional keyword-only `out_unmapped` parameter. Callers that pass an empty dict receive a per-MIDI record of every silently-skipped percussion note (`{midi: {"count": int, "times": [float, ...]}}`, times capped at 100 samples per note). This lets the editor plugin show a warning + manual-mapping UI on import instead of silently dropping unmapped notes. Default behavior unchanged for callers that don't opt in.

- **Drum support from scratch** — drums are now a first-class arrangement type with their own JSON payload on disk and their own WS stream to the highway. New `lib/drums.py` defines the closed piece-id vocabulary (kick, snare, snare_xstick, hh_closed/open/pedal, tom_hi/mid/low/floor, crash_l/r, splash, china, ride, ride_bell), default GM-MIDI mappings, three preset lane configurations, and a permissive `drum_tab.json` validator. `lib/sloppak.py::load_song` reads the manifest's optional top-level `drum_tab:` key, parses + validates the JSON, and surfaces it on `LoadedSloppak.drum_tab`; the load stays permissive so a missing or malformed tab silently disables drums rather than failing the sloppak load. `/ws/highway/{filename}` gains two new message types — `drum_tab` (metadata + kit legend) and chunked `drum_hits` (500 hits per frame, same chunking as notes) — exposed to renderers via `bundle.drumTab`. `song_info` carries a `has_drum_tab` flag so viz pickers can auto-activate the drums highway regardless of which guitar arrangement is selected. `lib/gp2rs.py::convert_drum_track_to_drumtab` converts a Guitar Pro drum track to a `drum_tab.json` dict, preserving velocity verbatim, mapping hi-hat openness through the canonical piece-ids, and flagging flam / ghost / cymbal-choke articulations from GP effects. `lib/midi_import.py` gains `list_drum_tracks` + `convert_drum_track_from_midi` (channel-9 only) with heuristic flam-collapse (≤30 ms same-piece) and choke detection (cymbal note-off ≤120 ms). `docs/sloppak-spec.md` §5.3 promotes drum_tab from worked-example to canonical with the closed piece-id table and wire format. Sloppaks without a drum_tab are unaffected; legacy drums-as-guitar-notes sloppaks keep playing via the drums plugin's fallback decoder.
- **Loose folder support** — a directory containing an audio file + arrangement XMLs, with optional `manifest.json` and album art, is now discovered, indexed, and playable as a first-class library format alongside Sloppak. The scanner walks `DLC_DIR` for non-preview audio files and treats each parent directory that also contains XMLs as a loose song. Metadata follows a `manifest.json` → XML tags → folder-name priority chain (see `lib/loosefolder.py`). Songs are tagged `format: "loose"`, render an amber `FOLDER` badge in the library, and are filterable via the new "Folder" option in the format dropdown. Audio uses the shared vgmstream/`convert_wem` pipeline, cached under `AUDIO_CACHE_DIR`. The chart `<offset>` from the first non-vocals XML is now propagated to the frontend via `song_info.offset` and applied in `highway.setTime()` so loose folders authored against non-silence-padded audio stay in sync. Pairs with the companion `feedBack-plugin-loosefolder` plugin which adds an in-player Fix Sync UI for nudging and saving offset corrections.
- Highway note-state hook (#254). New `highway.setNoteStateProvider(fn)` lets a scorer plugin publish a per-note judgment (`'hit'` / `'active'` for a sustain currently held correctly / `'miss'`, or `{ state, alpha, color }`) so the renderer lights up the **gem itself** on a correct hit and keeps a sustain trail glowing while it's still being played right — instead of a separate overlay ring near the note. The built-in 2D highway honors it in `drawNote` / `drawSustains` / the chord-frame path (bright string colour + additive halo on hits, bright vs dim sustain trail, faint red wash on misses); the bundled 3D highway reads the same data via `bundle.getNoteState` (bright string-tinted outline + bright body + glowing sustain on hit/active, red outline + suppressed body on miss). Custom renderers opt in by calling `bundle.getNoteState(note, chartTime)`. note_detect registers the provider (and still owns its HUD / diagnostic miss markers / "currently detected" indicator); renderers that ignore the hook simply don't light gems. On a confirmed hit/active the renderers add a contained "sparkle/sizzle" on the note — the 2D highway: additive throbbing halo + flickering hot core + crackling spark lines (+ an expanding shockwave ring on a fresh strike) on the gem and a glowing/jittery sustain trail; the 3D highway: a few twinkling bright dots and short crackling arc segments hugging the note's rectangle (no bloom past the note), drawn on its overlay and projected through the camera so they ride the note. Also adds `highway.isDefaultRenderer()` so overlays that position with the 2D-highway helpers (`project` / `fretX`) can skip rendering when a custom renderer is active — fixes note_detect's miss markers appearing in random places over the 3D highway. New 3D-highway setting **Show note preview on the fretboard** (on by default) toggles the board-projection ghost — the translucent preview of the upcoming note on the fretboard surface. (Note: the companion change in the **note_detect plugin repo** turns its full-screen green/red edge flash off by default and adds a toggle to re-enable it — ships separately with note_detect, not in this feedBack release.)
- Diagnostic bundle export (#166). New "Export Diagnostics" + "Preview Bundle" buttons in Settings produce a single redacted zip combining server logs (tail of `LOG_FILE`), system info (Python/OS/version), hardware probe (CPU model + cores + freq + RAM, GPU via `nvidia-smi`/`rocm-smi`/`system_profiler`, container/Electron/bare runtime detection), full plugin inventory with git SHA + remote URL (read directly from `.git/HEAD` so it works in minimal runtime images without `git` installed) + orphan/failed-to-load detection, the browser console transcript (all levels: log/info/warn/error/debug + window.onerror + unhandledrejection, 500-entry ring buffer), browser hardware (WebGL/WebGPU adapter info, navigator + userAgentData), filtered localStorage, and per-plugin contributed diagnostics. Top-level `manifest.json` lists every file with its versioned schema id (`system.hardware.v1`, `client.console.v1`, etc.) so AI agents can dispatch by schema. Redaction is on by default: DLC paths, song filenames (`<song:HASH8>` stable per-bundle), IPv4/IPv6 addresses, bearer tokens, and `key=`/`token=` query strings are replaced. Plugins opt their backend diagnostics in via a new `diagnostics` manifest field (`server_files` allowlist mirroring `settings.server_files` semantics, plus an optional `callable: "<module>:<function>"` resolved lazily via `load_sibling`). Frontend plugins push diagnostics via `window.feedBack.diagnostics.contribute(plugin_id, payload)`. Three new endpoints: `POST /api/diagnostics/export`, `GET /api/diagnostics/preview`, `GET /api/diagnostics/hardware`. Full bundle format spec in `docs/diagnostics-bundle-spec.md`.
- Structured logging bootstrap (phase 1 of #155). Three new environment variables control server log output: `LOG_LEVEL` (default `INFO`), `LOG_FORMAT` (`text` for coloured console, `json` for one-JSON-object-per-line suitable for Loki/ELK/Promtail), and `LOG_FILE` (optional path, rotated at 10 MB with 5 backups). HTTP responses now include a `X-Request-ID` correlation header (via `CorrelationIdMiddleware`); the same request ID appears as `request_id` in structured log lines emitted via the stdlib `logging` / `structlog` APIs during that request.
- Structured logging migration completed (phase 2 of #155, #159, #242). The 42 `print()` calls and 6 `traceback.print_exc()` calls across `server.py` and `lib/` have been migrated to levelled `feedBack.*` loggers. Silent `except: pass` blocks in `lib/sloppak.py` and `lib/sloppak_convert.py` now surface as `log.warning` / `log.debug` with the exception attached. WebSocket handlers (`highway_ws`, `ws_retune`) bind a `ws_conn_id` contextvar at accept time so every log line within a session carries a connection ID. A CI grep guard in `.github/workflows/tests.yml` fails the build if either `print(` or `traceback.print_exc(` reappears in `server.py` or `lib/`.
- **Lyrics Karaoke plugin** — end-to-end karaoke setup for Sloppak songs in one workflow. The setup screen shows a per-song checklist (vocals stem / synced lyrics / per-syllable pitch) and a single "Build Karaoke" button that runs whatever's missing: Whisper alignment of pasted lyric text against the vocals stem, then `librosa.pyin` pitch extraction. Both artifacts persist inside the Sloppak (`lyrics.json`, `vocal_pitch.json`). In the player, a "Karaoke" toggle swaps the text-lyrics overlay for a horizontal pitch ribbon (one bar per syllable, vertically positioned by pitch, sweeping playhead).
- Settings export/import (#113). Two buttons on the Settings page bundle server config, browser localStorage, and opted-in plugin server-side files into a single versioned JSON file for backup, migration, or sharing a calibrated setup. Server-side import is all-or-nothing for safety-critical failures: phase-1 validates the entire bundle (schema, path-traversal, encoding) before any disk writes; phase-2 commits each file via temp+rename. Plugin-state mismatches between export and import are handled leniently: files referenced for a plugin that isn't loaded are skipped with a warning, files referenced for a plugin whose manifest no longer declares them are skipped with a warning, and localStorage is merged (not cleared) so first-run defaults from plugins installed after the export are preserved. Path-traversal, absolute paths, schema mismatch, and decode failures remain hard refusals. Plugins opt their server-side files in by declaring `settings.server_files` in `plugin.json` (list of relpaths under `CONFIG_DIR`; trailing `/` denotes a directory).
- Library filtering by parts present or missing (#129, #69). New right-side Filters drawer (single button next to the format/sort row, with active-filter count badge and dismissible chips below) lets you require or exclude arrangements (Lead/Rhythm/Bass/Combo), specific stems on Sloppaks (drums/bass/vocals/piano/other), lyrics, and tuning. Multi-select within an axis is OR (Lead OR Rhythm); cross-axis is AND. State persists across reloads. New endpoint `GET /api/library/tuning-names` returns distinct tunings present in the library, ordered by musical distance.
- Sort library by year (#128). Two new options in the sort dropdown: "Year (newest)" and "Year (oldest)". Songs without a year are pushed to the bottom for both directions.
- **`highway.getLyrics()` accessor.** `createHighway()` now exposes the parsed timed lyric syllables (`[{t, d, w}]`) via `getLyrics()`, mirroring `getBeats()`/`getSections()`, so overlay plugins can render karaoke without opening a second highway WebSocket. Pure accessor; no behavior change.

### Changed
- **Perf (3D highway, feedBack#226)**: pre-warm `plugins/highway_3d/screen.js` object pools at board init. Previously the pool factory grew lazily on first `.get()` past the high-water mark, allocating a fresh `T.Mesh` mid-rAF on dense 7/8-string charts and stalling those frames; the meshes were then permanently added to `noteG` (the pool only hides on `reset()`, never removes), bloating the scene graph for the rest of the session. Pre-warming spends the cost up front. Fold the per-frame `updateStringHighlights()` per-string loop with the post-call `mGlow`/`mAccentCore` emissive writes — one walk over the per-string scratch arrays instead of two. Replace `longestConsecutiveRun`'s per-call array allocations with a `{start, len}` index pair (trades two per-call sub-array allocations for one small 2-key object — net reduction in per-visible-chord allocation churn). Opt-in perf bench harness via `?h3dbench=1` URL param: `console.log` p50/p95/max for six update() segments every 5 seconds; when the URL flag is absent the mark helpers are bound to empty functions at renderer-instance init (each `createHighway()` panel re-checks the flag), so the hot-path calls are no-ops with negligible overhead (typically JIT-inlined).
- **License**: Relicensed to AGPL-3.0-only. Prior versions claimed MIT in the README, but the bundled desktop build statically links JUCE 8 (AGPL-3.0), so AGPL terms have effectively governed the desktop distribution since JUCE was added. AGPL-3.0-only is now the canonical license for the project — see [LICENSE](LICENSE) and [CONTRIBUTING.md](CONTRIBUTING.md) (DCO sign-off + plugin licensing policy). Bundled and vendored third-party code keeps its original license.
- Tuning sort is now ordered by musical distance from E Standard (#22) instead of alphabetical: E Standard first, then Drop D / F Standard at distance 2, then Eb Standard / F# Standard at distance 6, etc. Within a magnitude tier, down-tuned variants come before up-tuned, then alphabetical.
- Settings page restructured into separate "FeedBack" (core) and "Plugins" sections, with each plugin's settings rendered as a collapsible panel (collapsed by default). "Plugin Updates" moved into the Plugins section.
- **Lyrics Sync** is now a redirect stub. Its alignment + save endpoints moved into the new Lyrics Karaoke plugin alongside the pitch extraction. Existing nav entries and bookmarks land on a "moved" page that auto-redirects to the merged plugin.

### Security
- **Path traversal in archive extractors and library path resolution.** `lib/sloppak.py::_unpack_zip` and `server.py::_resolve_dlc_path` previously concatenated attacker-controlled entry names or filenames directly onto the extraction or library directory, so a crafted sloppak zip member or library filename with `..` segments, an absolute path, or backslash separators could write or read outside the intended directory. Any code path that unpacks a user-supplied archive (library upload, click-to-play, retune) or resolves a library path was reachable. Both locations now delegate to a new `lib/safepath.py::safe_join` helper that resolves each destination once and rejects entries that don't fall under the target directory; rejected entries are logged and skipped, the rest of the archive still extracts. The stem-split paths in `lib/sloppak_convert.py::split_stems` and `scripts/split_stems.py` previously called `ZipFile.extractall()` directly on user-supplied sloppaks; both now delegate to the same hardened `lib/sloppak.py::_unpack_zip` so every sloppak-unzip site in the codebase shares one containment guarantee. Tests in `tests/test_archive_traversal.py` and `tests/test_safepath.py` pin the contract for `../`, deep traversal, absolute paths, mixed `subdir/../../` forms, Windows-style separators, NUL bytes, names that resolve to the unpack root, and symlinked roots.

### Fixed
- E Standard retune now stays metadata-consistent across a chart's arrangement files (feedBack-plugin-notedetect#50). Previously the retune path could shift the audio and update manifests while leaving some arrangement metadata untouched, so `load_song()` later exposed the *original* tuning at runtime. `lib/retune.py` now updates every arrangement's tuning metadata consistently before applying the E Standard tuning, and raises on a partial update instead of silently packing split tuning metadata. EStd files generated before this fix should be re-converted so their metadata is consistent.
- Keyboard shortcut help now opens from the Player/3D Highway context when Linux/Electron reports Shift+Slash as `key="/"`, including while player controls such as the visualization picker are focused (#598).
- 3D Highway left-handed mode now has regression coverage for fret-axis mirroring, board rebuilds on runtime lefty changes, and mirrored camera state including the lookahead target and shoulder offset; the maintainer guide no longer claims the renderer ignores `bundle.lefty` (#321).
- Chord-level `fretHandMute` is now parsed into each note's `fret_hand_mute` (wire `fhm`) instead of being folded into `mute` (`mt`), matching `_parse_note` and preserving wire-format fidelity for both the template-expanded (synthetic-note) and explicit-`chordNote` paths. The 3D highway renders the fret-hand-mute X for `mt` *or* `fhm` notes, so the muted-chord overlay still shows. Also fixes the per-note fret-connector label vanishing exactly at the hit line (the fade now holds full opacity through `dt = 0`).
- `gp2rs` now respects the time-signature denominator when emitting ebeat subdivisions, fixing misaligned beat grids in 6/8 and other non-quarter-note meters.
- Settings dropdowns (Default Arrangement, Platform Filter) now persist immediately when changed. Previously a dropdown selection was only written to `config.json` when an unrelated "Save" button (Library Folder or Demucs Server) was clicked, so picking a default arrangement and navigating away silently discarded it. Both `<select>` controls now POST the single changed field on `change` via the partial-merge `/api/settings` endpoint, matching the auto-save behaviour of the A/V Sync Offset and mastery sliders. The text inputs (Library Folder Path, Demucs Server URL) keep their explicit Save buttons. Autosaves are sent through a single client-side queue (one request in flight at a time, in selection order), and the `POST /api/settings` handler now serializes its read-modify-write of `config.json` under a lock so concurrent partial updates can no longer overwrite each other and drop a key. The config write is also atomic (temp + rename) and `/api/settings/import` shares the same lock, so readers never observe a half-written file and a settings import can't race a concurrent partial save.
- Demucs stem split failing on Windows desktop with `OSError: Could not load this library: libtorchcodec_core4.dll` or `ImportError: TorchCodec is required for save_with_torchcodec`. The demucs subprocess now bootstraps a `torchaudio.save` → `soundfile.write` shim before importing demucs, sidestepping the torchcodec dependency entirely. The override stays in place across torchaudio versions — soundfile's WAV writes are behaviorally equivalent for demucs's float32 outputs.
- Splitscreen pop-out windows briefly flashed the library/song grid before showing the popped panel. A popup loads the full app (whose default screen, `#home`, is the library) and only swaps to the player once the splitscreen plugin loads; app init now detects `?ssFollower=1` and switches to the player screen up front, so the popup shows player chrome the whole time.
- Sloppak assembly dropped all tone data — affected sloppaks showed no signal chain in the Tones plugin and no tone-change markers on the highway. The assembler (`lib/sloppak_convert.py`) now lifts each arrangement's tones from the source chart via the new `lib/tones.py` helper and embeds them inline in the arrangement JSON under a `tones` key (`base`, `changes`, `definitions` — see `docs/sloppak-spec.md` §3.9). The highway WebSocket reads `base`/`changes` for sloppaks, and the Tones plugin (≥ 1.1.0) reads `definitions` to render the gear chain. Sloppaks built before this release carry no tone data and must be rebuilt from their source chart to gain it.
- Tab View (feedBack-plugin-tabview ≥ 3.0.1): the bottom row of tablature was permanently hidden behind the player controls bar (#336). The overlay reserved 60px at the *top* (clearing the transparent HUD) and extended all the way to the bottom of `#player`, where the opaque `#player-controls` (z-index 10) drew over the last row. The overlay now measures `#player-hud` and `#player-controls` dynamically and insets both edges; a `ResizeObserver` on the controls bar re-runs the inset when it wraps to a second row on narrow viewports.
- Tab View (feedBack-plugin-tabview ≥ 3.0.1): the cursor highlight led playback by roughly one beat (#336). alphaTab snaps `tickPosition` to the start of the *next* beat, so the cursor would race ahead by 500ms+ at typical tempos. The plugin now sends `tickPosition` one beat earlier so the snap lands on the current beat, and the highlight overlay tracks the bar cursor (`.at-cursor-bar`) instead of the next-beat cursor (`.at-cursor-beat`).

### Migration notes
- **Constitution amended to 1.1.0 (Principle II — Vanilla Frontend).** Prebuilt Tailwind (`static/tailwind.min.css`) is now codified as non-negotiable: no Play CDN / runtime CSS JIT anywhere, core or plugin. Plugin authors: a plugin that uses Tailwind classes not guaranteed in core — especially arbitrary values like `w-[37px]` — MUST ship its own compiled stylesheet via the new `styles` manifest key, built with `corePlugins.preflight = false`. Plugins that use only core-guaranteed utilities, or that ship no Tailwind at all, need no change. Contributors: after adding any Tailwind class to core or a bundled plugin, run `bash scripts/build-tailwind.sh` and commit the regenerated CSS, or the `tailwind-fresh` CI job fails.
- The library filters depend on three new columns (`stem_ids`, `tuning_name`, `tuning_sort_key`) that are populated as songs are scanned. If filters look empty after upgrading, run **Settings → Full Rescan** to repopulate; alternatively the periodic background rescan picks them up over time.

## [0.2.4] - 2026-04-22

### Added
- Version badge in navbar (`/api/version` endpoint + `VERSION` file)
- `CHANGELOG.md` and semantic versioning
- Step Mode plugin
- `gp2midi` improvements and expanded test coverage
- Note Detection plugin factory-pattern refactor with multi-instance/splitscreen support
- Per-panel note detection in Split Screen plugin with M/L/R channel routing for multi-input interfaces

### Fixed
- `SLOPPAK_CACHE_DIR` moved to `CONFIG_DIR` for AppImage compatibility
- Improved error message when plugin requirements fail to install