feat(achievements): local engine + tabbed Profile shell (epic PR1) (#587)

Adds the Achievements & Feats of Power local engine, fully offline.

Core (static/v3/profile.js): the Profile screen becomes tabbed exactly
like v3 Settings (.fb-tabbar/.fb-tab/.fb-tabpanel, active tab persisted in
localStorage 'v3-profile-tab'). A Profile (main) tab carries the existing
cards + a Feats trophy-shelf mount (#v3-profile-feats-slot, earned-only),
and an Achievements tab carries a plugin mount
(#v3-profile-achievements-mount) + empty-state note. A new
`v3:profile-rendered` event fires after every render so the plugin
re-injects (mirrors v3:settings-rendered).

New bundled plugin (plugins/achievements/): SQLite engine
(unlocks/counters/comp_ledger/sync_queue) with pure threshold/criterion
math in the testable sibling engine.py (P-V); routes activity/
report-unlock/report-criterion/catalog/earned/feats/remove-me. Feats read
activity counters only (batched song:ended POST; notes only when notedetect
present — graceful degradation); competency Achievements evaluate from
progression events only — the integration law, never crossed. Catalogue is
always shown (locked=greyed), grouped by the real progression paths
(Global/Guitar/Bass/Drums/Keys, auto-extending) with per-category earned
badges. Versioned window.feedBack.achievements registration API with the
__feedBackAchievementsPending load-order queue + achievements:ready event.

Verified natively (uvicorn) end-to-end + Playwright (tabbar, earned-only
Feats shelf, greyed catalogue, registration API, zero console errors);
24 plugin tests pass incl. the integration-law assertion.

Opt-in/privacy/data-min gate (PR2) and the hosted wall (PR3) follow.

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

CHANGELOG.md

@@ -8,6 +8,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## [Unreleased]
 
 ### Added
+- **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.