fix(build): move appstate.py + routers/ under lib/ so the desktop app ships them

The packaged desktop app died at startup:

    File ".../Resources/slopsmith/server.py", line 71, in <module>
        import appstate
    ModuleNotFoundError: No module named 'appstate'

feedback-desktop's scripts/bundle-slopsmith.sh copies a HARDCODED list of core
files into the bundle -- server.py, VERSION, lib/, data/, static/,
plugins/__init__.py. The root-level appstate.py (#833) and routers/ (#834)
shipped fine in Docker, passed every test, and were silently dropped from the
packaged app.

Both now live under lib/, the one core directory every packaging path already
copies wholesale -- Dockerfile `COPY lib/`, docker-compose.yml, and the desktop
bundler's `cp -r lib` -- and that all three put on sys.path (on Windows via the
embeddable-Python ._pth, where PYTHONPATH is ignored: build-windows.sh writes
`../slopsmith` and `../slopsmith/lib`). No feedback-desktop change and no new
release are needed for this to take effect.

lib/ is also the CORRECT home under Principle V, and always was once the design
settled: with the injection seam, appstate.py constructs nothing and does no
import-time IO, and a route module only builds an APIRouter. The premise that
forced root placement -- "appstate opens sqlite at import" -- stopped being true
when configure() replaced ownership. The Dockerfile / .dockerignore /
docker-compose.yml entries added for the root layout are reverted; nothing else
in core changes (git mv, so --follow survives).

tests/test_packaging.py is the guard: it walks server.py's module-level imports,
keeps the ones resolving inside this repo, and fails if any lives outside a
directory the packagers copy -- with the ModuleNotFoundError spelled out. So the
next root-level core module can't ship broken. Negative-checked: restoring
appstate.py to the root fails it; the message names the file and the four
packaging files a root module would have to teach.
(It also has to skip `origin in {"built-in","frozen"}` -- on 3.14 the frozen
stdlib reports origin="frozen", and Path("frozen").resolve() lands inside the
repo, which flagged `os` and `stat` as first-party.)

Verified: the bundler's copy replicated exactly into a temp dir and booted with
PYTHONPATH=<bundle>:<bundle>/lib -- `import server`, `import appstate`,
`import routers.audio_effects` all resolve, appstate.meta_db is server.meta_db,
143 routes. The same simulation against origin/main reproduces the production
ModuleNotFoundError. pytest 2398 passed (2348 + 50 new); route table still
identical to origin/main (paths, methods, order); docker build context reaches
lib/appstate.py and lib/routers/ with no __pycache__; native uvicorn boot smoke
serves /api/version, /api/library, the moved audio-effects router, and all three
migrated plugins' src/ graphs; eslint 0 errors.

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

CHANGELOG.md

@@ -7,7 +7,64 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Fixed
+- **The packaged desktop app could not start (`ModuleNotFoundError: No module named
+  'appstate'`).** feedback-desktop's `scripts/bundle-slopsmith.sh` copies a *hardcoded
+  list* of core files into the app bundle — `server.py`, `VERSION`, `lib/`, `data/`,
+  `static/`, `plugins/__init__.py`. The root-level `appstate.py` and `routers/` added in
+  R3 shipped correctly in Docker and passed every test, and were then silently dropped
+  from the packaged app, which died at startup. Both now live under **`lib/`** — the one
+  core directory the Dockerfile (`COPY lib/`), `docker-compose.yml`, and the desktop
+  bundler (`cp -r lib`) all copy wholesale, and that all three put on `sys.path` (on
+  Windows via the embeddable-Python `._pth`, where `PYTHONPATH` is ignored). This needs no
+  change in feedback-desktop and no new release to take effect. Placing them there is also
+  correct under Principle V: with the injection seam, `appstate.py` constructs nothing and
+  does no import-time IO, and a route module only builds an `APIRouter`. The
+  `Dockerfile` / `.dockerignore` / `docker-compose.yml` entries added for the root layout
+  are reverted. New `tests/test_packaging.py` walks `server.py`'s module-level imports and
+  fails if any first-party module resolves outside a directory the packagers copy, so the
+  next root-level module can't ship broken.
+
+### Added
+- **`routers/` — the first extracted route module (R3).** The five audio-effects mapping
+  endpoints move out of `server.py` into `lib/routers/audio_effects.py` as a
+  `fastapi.APIRouter`, mounted with `app.include_router(...)` **at the point in the file
+  where they used to be defined** — FastAPI matches routes in registration order, so the
+  mount site preserves it. Verified: the full 143-route table (paths, methods, *and*
+  order) is byte-for-byte identical to `main`. Bodies are verbatim; the only edits are
+  the decorator receiver (`@app.get` → `@router.get`) and the singleton read
+  (`audio_effect_mappings` → `appstate.audio_effect_mappings`, a module attribute
+  resolved at call time). This proves the seam from #833 under a real consumer, including
+  the second slot. The `_demo_mode_guard` middleware still blocks all four moved write
+  routes with 403, and `Query(...)` validation still 422s — both checked against a running
+  server. `server.py`: **9,445 → 9,386 lines**.
+- **`appstate.py` — the router seam (R3).** Route modules moving out of `server.py`
+  need `meta_db` and friends but must not `import server`, or the import graph goes
+  circular the moment `server` imports them back. So `server.py` keeps *constructing*
+  its singletons and now **injects** them once — `appstate.configure(meta_db=…,
+  audio_effect_mappings=…)` — and a router reads them back as module attributes at call
+  time (`import appstate; appstate.meta_db.…`). This is the Python analogue of the
+  frontend refactor's injected `configureX({…})` seams and of the plugin
+  `setup(app, context)` contract: dependencies flow one way, `server → routers →
+  appstate`. Two properties are load-bearing and pinned by `tests/test_appstate.py`:
+  (1) `import appstate` constructs nothing and touches no disk, so the ~49 test fixtures
+  that `sys.modules.pop("server")` + re-import (to rebuild `meta_db` under a patched
+  `CONFIG_DIR`) keep working untouched — a singleton *owned* by `appstate` would survive
+  that pop and go stale; (2) reads must be late-bound (`appstate.meta_db`, never
+  `from appstate import meta_db`), since a `from` import freezes the binding and defeats
+  both a later `configure()` and `monkeypatch.setattr` — the same read-only-binding trap
+  as ES `import`. `configure()` rejects an unknown slot rather than silently creating a
+  global nothing reads, and the suite asserts `server` actually calls it (a seam whose
+  wiring can no-op undetected is worse than no seam). Lives at `lib/appstate.py`.
+
 ### Changed
+- **`AudioEffectsMappingDB` moved out of `server.py` into `lib/audio_effects_db.py`
+  (R3, move-only).** The core-owned song/tone → provider routing index follows
+  `MetadataDB` out of the host file, byte-identical apart from the same constructor
+  seam (`__init__` takes `config_dir`; `audio_effect_mappings = AudioEffectsMappingDB(CONFIG_DIR)`),
+  so the module does no IO at import. The singleton stays in `server.py`; no route,
+  no test and no `monkeypatch.setattr(server, …)` target moves. `server.py`:
+  **9,705 → 9,433 lines**.
 - **`MetadataDB` moved out of `server.py` into `lib/metadata_db.py` (R3, move-only).**
   The library metadata cache — the `MetadataDB` class (4,018 lines) plus the query
   helpers it owns (keyset paging cursors, the tuning grouping key, smart-arrangement

docs/size-exemptions.md

@@ -55,7 +55,8 @@ without a *signed* exemption" is unenforceable.
 ## Planned, NOT exempt (owned by split plans — listed so nothing falls between states)
 
 core `static/app.js` (11,852) · `static/highway.js` (4,168, whole file) · `server.py`
-(9,705 — was 14,037; ratcheted by the R3 `MetadataDB` extraction) ·
+(9,386 — was 14,037; ratcheted by the R3 `MetadataDB` + `AudioEffectsMappingDB`
+extractions and the first `routers/` module) ·
 `lib/metadata_db.py` (4,373 — new in R3; the `MetadataDB` class alone is 4,018 lines
 and is a monolith in its own right, to be split per-table once the router train
 lands) · `static/v3/songs.js` (4,134) · `static/capabilities/audio-session.js`

lib/appstate.py

@@ -0,0 +1,81 @@
+"""Shared application state — the seam that lets route modules reach core
+singletons without importing ``server``.
+
+``server.py`` is the host: it owns the FastAPI ``app``, constructs the DB
+singletons, and runs the lifecycle. As routes move out into ``routers/`` (R3),
+those modules need ``meta_db`` and friends — but they must not ``import
+server``, or the import graph goes circular the moment ``server`` imports them
+back.
+
+So ``server`` **injects** its singletons here once, at the point it builds them::
+
+    # server.py
+    meta_db = MetadataDB(CONFIG_DIR)
+    appstate.configure(meta_db=meta_db, ...)
+
+and a router reads them back as **module attributes, at call time**::
+
+    # routers/artists.py
+    import appstate
+
+    @router.get("/api/artist/{name}/page")
+    def artist_page(name):
+        return appstate.meta_db.artist_page(name)
+
+This is the Python analogue of the injected `configureX({...})` seams the
+frontend refactor uses (stems' ``configureStreaming``, studio's
+``configureAudioGraph``, the editor's ``src/host.js``), and of the plugin
+``setup(app, context)`` contract in Principle III: dependencies flow one way,
+``server -> routers -> appstate``, and nothing imports back up.
+
+Two properties this shape buys, both load-bearing:
+
+* **``import appstate`` performs no IO and constructs nothing.** ``server``
+  still owns construction, so the ~49 test fixtures that do
+  ``sys.modules.pop("server")`` + re-import (to rebuild ``meta_db`` under a
+  patched ``CONFIG_DIR``) keep working untouched — a singleton *owned* here
+  would survive that pop and go stale.
+* **Reads are late-bound.** Routers must use ``appstate.meta_db``, never
+  ``from appstate import meta_db`` — a ``from`` import freezes the binding at
+  its current value, so a later ``configure()`` (or a
+  ``monkeypatch.setattr(appstate, "meta_db", fake)``) would not reach the
+  router. This is the same read-only-binding trap as ES ``import``.
+
+Defaults are ``None`` on purpose: they are inert but *type-honest*, so a router
+that runs before ``configure()`` fails loudly on ``NoneType`` instead of
+quietly operating on a stand-in.
+
+Slots are added here only when a router actually needs one — this is a seam,
+not a grab-bag for everything in ``server.py``.
+
+**Why this lives in ``lib/`` and not the repo root.** Because it constructs
+nothing and does no import-time IO, it satisfies Principle V's rule for ``lib/``
+modules — and ``lib/`` is the only core directory every packaging path already
+copies: the Dockerfile (``COPY lib/``), ``docker-compose.yml``, and
+feedback-desktop's ``bundle-slopsmith.sh`` (``cp -r lib``). All three also put
+both the bundle root and ``lib/`` on ``sys.path``. A root-level module ships in
+Docker but is silently dropped from the packaged desktop app, whose bundler
+copies a hardcoded file list — that regression is what moved this file here.
+"""
+
+# The singletons routers may read. Every name here must also be a `_SLOTS` key.
+meta_db = None
+audio_effect_mappings = None
+
+# Declared up front so `configure()` can reject a typo'd or stale keyword
+# instead of silently creating a new global that nothing ever reads. A seam
+# whose wiring can no-op undetected is worse than no seam.
+_SLOTS = frozenset({"meta_db", "audio_effect_mappings"})
+
+
+def configure(**kwargs) -> None:
+    """Publish `server`'s singletons into this module. Called once per
+    `server` import (and again on re-import), so it must be idempotent."""
+    unknown = set(kwargs) - _SLOTS
+    if unknown:
+        raise TypeError(
+            f"appstate.configure() got unknown slot(s): {sorted(unknown)}. "
+            f"Known slots: {sorted(_SLOTS)}. Add the name to _SLOTS if a router "
+            f"genuinely needs it."
+        )
+    globals().update(kwargs)

lib/audio_effects_db.py

@@ -0,0 +1,287 @@
+"""Core-owned song/tone -> audio-effect-provider mapping index.
+
+Extracted verbatim from ``server.py`` (R3). ``server.py`` still owns the
+``audio_effect_mappings`` singleton; this module only supplies the class, so
+nothing here touches config paths at import time — the caller passes
+``config_dir`` in.
+"""
+
+import json
+import sqlite3
+import threading
+from pathlib import Path
+
+
+class AudioEffectsMappingDB:
+    """Core-owned public song/tone -> provider mapping index.
+
+    Providers own the preset/chain rows addressed by provider_ref. Core owns
+    the cross-provider routing index and the active mapping per song/tone.
+    """
+
+    def __init__(self, config_dir: Path):
+        config_dir.mkdir(parents=True, exist_ok=True)
+        self.db_path = str(config_dir / "audio_effects.db")
+        self.conn = sqlite3.connect(self.db_path, check_same_thread=False)
+        self.conn.execute("PRAGMA journal_mode=WAL")
+        self.conn.execute("PRAGMA foreign_keys=ON")
+        self.conn.execute("""
+            CREATE TABLE IF NOT EXISTS audio_effect_mappings (
+                id INTEGER PRIMARY KEY AUTOINCREMENT,
+                song_key TEXT NOT NULL,
+                filename TEXT NOT NULL DEFAULT '',
+                tone_key TEXT NOT NULL,
+                provider_id TEXT NOT NULL,
+                provider_ref TEXT NOT NULL,
+                label TEXT NOT NULL DEFAULT '',
+                source TEXT NOT NULL DEFAULT 'manual',
+                metadata_json TEXT NOT NULL DEFAULT '{}',
+                created_at TEXT NOT NULL DEFAULT (datetime('now')),
+                updated_at TEXT NOT NULL DEFAULT (datetime('now')),
+                UNIQUE(song_key, tone_key, provider_id)
+            )
+        """)
+        self.conn.execute("""
+            CREATE TABLE IF NOT EXISTS audio_effect_active_mappings (
+                song_key TEXT NOT NULL,
+                tone_key TEXT NOT NULL,
+                mapping_id INTEGER NOT NULL,
+                updated_at TEXT NOT NULL DEFAULT (datetime('now')),
+                PRIMARY KEY (song_key, tone_key),
+                FOREIGN KEY (mapping_id) REFERENCES audio_effect_mappings(id) ON DELETE CASCADE
+            )
+        """)
+        self.conn.execute(
+            "CREATE INDEX IF NOT EXISTS idx_audio_effect_mappings_provider "
+            "ON audio_effect_mappings(provider_id)"
+        )
+        self.conn.execute(
+            "CREATE INDEX IF NOT EXISTS idx_audio_effect_mappings_filename "
+            "ON audio_effect_mappings(filename)"
+        )
+        self.conn.commit()
+        self._lock = threading.Lock()
+
+    @staticmethod
+    def _text(value, *, field: str, limit: int, allow_empty: bool = False) -> str:
+        if value is None:
+            text = ""
+        elif not isinstance(value, str):
+            raise ValueError(f"{field} must be a string")
+        else:
+            text = value.strip()
+        if not text and not allow_empty:
+            raise ValueError(f"{field} is required")
+        if len(text) > limit:
+            raise ValueError(f"{field} is too long")
+        return text
+
+    @staticmethod
+    def _mapping_id(value) -> int | None:
+        # Bind only values SQLite can store as an INTEGER; an out-of-range id is a
+        # clean miss (404), not a 500 at bind time.
+        if isinstance(value, int) and not isinstance(value, bool) and -(2 ** 63) <= value < 2 ** 63:
+            return value
+        return None
+
+    @staticmethod
+    def _field(data: dict, *keys):
+        # Select the first present snake/camel alias by key, not by truthiness, so a
+        # falsey non-string value (false/0) still reaches _text() and is rejected
+        # instead of being silently swallowed by an `or` chain.
+        for key in keys:
+            if key in data:
+                return data[key]
+        return None
+
+    @staticmethod
+    def _metadata(value) -> str:
+        if value is None:
+            return "{}"
+        if not isinstance(value, dict):
+            raise ValueError("metadata must be an object")
+        encoded = json.dumps(value, ensure_ascii=True, sort_keys=True)
+        if len(encoded) > 8192:
+            raise ValueError("metadata is too large")
+        return encoded
+
+    @staticmethod
+    def _row(row) -> dict | None:
+        if row is None:
+            return None
+        metadata = {}
+        try:
+            metadata = json.loads(row[8]) if row[8] else {}
+        except Exception:
+            metadata = {}
+        return {
+            "id": int(row[0]),
+            "song_key": row[1],
+            "filename": row[2] or "",
+            "tone_key": row[3],
+            "provider_id": row[4],
+            "provider_ref": row[5],
+            "label": row[6] or "",
+            "source": row[7] or "manual",
+            "metadata": metadata if isinstance(metadata, dict) else {},
+            "created_at": row[9] or "",
+            "updated_at": row[10] or "",
+            "active": bool(row[11]),
+        }
+
+    def _select_sql(self) -> str:
+        return """
+            SELECT m.id, m.song_key, m.filename, m.tone_key, m.provider_id,
+                   m.provider_ref, m.label, m.source, m.metadata_json,
+                   m.created_at, m.updated_at,
+                   CASE WHEN a.mapping_id IS NULL THEN 0 ELSE 1 END AS active
+            FROM audio_effect_mappings m
+            LEFT JOIN audio_effect_active_mappings a
+              ON a.song_key = m.song_key AND a.tone_key = m.tone_key AND a.mapping_id = m.id
+        """
+
+    def list(self, *, song_key: str = "", filename: str = "", tone_key: str = "", provider_id: str = "") -> list[dict]:
+        clauses: list[str] = []
+        params: list[str] = []
+        song_key = self._text(song_key, field="song_key", limit=240, allow_empty=True)
+        filename = self._text(filename, field="filename", limit=500, allow_empty=True)
+        tone_key = self._text(tone_key, field="tone_key", limit=160, allow_empty=True)
+        provider_id = self._text(provider_id, field="provider_id", limit=96, allow_empty=True)
+        if song_key and filename:
+            clauses.append("(m.song_key = ? OR m.filename = ?)")
+            params.extend([song_key, filename])
+        elif song_key:
+            clauses.append("m.song_key = ?")
+            params.append(song_key)
+        elif filename:
+            clauses.append("(m.song_key = ? OR m.filename = ?)")
+            params.extend([filename, filename])
+        if tone_key:
+            clauses.append("m.tone_key = ?")
+            params.append(tone_key)
+        if provider_id:
+            clauses.append("m.provider_id = ?")
+            params.append(provider_id)
+        sql = self._select_sql()
+        if clauses:
+            sql += " WHERE " + " AND ".join(clauses)
+        sql += " ORDER BY m.song_key COLLATE NOCASE, m.tone_key COLLATE NOCASE, m.provider_id COLLATE NOCASE"
+        with self._lock:
+            rows = self.conn.execute(sql, params).fetchall()
+        return [self._row(row) for row in rows]
+
+    def get(self, mapping_id: int) -> dict | None:
+        mapping_id = self._mapping_id(mapping_id)
+        if mapping_id is None:
+            return None
+        with self._lock:
+            row = self.conn.execute(self._select_sql() + " WHERE m.id = ?", (mapping_id,)).fetchone()
+        return self._row(row)
+
+    def upsert(self, data: dict) -> dict:
+        if not isinstance(data, dict):
+            raise ValueError("mapping body must be an object")
+        filename = self._text(data.get("filename", ""), field="filename", limit=500, allow_empty=True)
+        song_key_raw = self._field(data, "song_key", "songKey")
+        if song_key_raw is None or song_key_raw == "":
+            song_key_raw = filename
+        song_key = self._text(song_key_raw, field="song_key", limit=240)
+        tone_key = self._text(self._field(data, "tone_key", "toneKey"), field="tone_key", limit=160, allow_empty=True)
+        provider_id = self._text(self._field(data, "provider_id", "providerId"), field="provider_id", limit=96)
+        provider_ref = self._text(self._field(data, "provider_ref", "providerRef"), field="provider_ref", limit=240)
+        label = self._text(data.get("label", ""), field="label", limit=160, allow_empty=True)
+        source = self._text(data.get("source", "manual"), field="source", limit=40, allow_empty=True) or "manual"
+        metadata_json = self._metadata(data.get("metadata", {}))
+        with self._lock:
+            self.conn.execute(
+                """
+                INSERT INTO audio_effect_mappings
+                    (song_key, filename, tone_key, provider_id, provider_ref, label, source, metadata_json, updated_at)
+                VALUES (?, ?, ?, ?, ?, ?, ?, ?, datetime('now'))
+                ON CONFLICT(song_key, tone_key, provider_id) DO UPDATE SET
+                    -- Only overwrite filename when a non-empty one was supplied; an
+                    -- omitted/empty filename must preserve the stored value (it's an
+                    -- alternate lookup key for list(..., filename=...)).
+                    filename=CASE WHEN excluded.filename <> '' THEN excluded.filename ELSE audio_effect_mappings.filename END,
+                    provider_ref=excluded.provider_ref,
+                    label=excluded.label,
+                    source=excluded.source,
+                    metadata_json=excluded.metadata_json,
+                    updated_at=datetime('now')
+                """,
+                (song_key, filename, tone_key, provider_id, provider_ref, label, source, metadata_json),
+            )
+            row = self.conn.execute(
+                "SELECT id FROM audio_effect_mappings WHERE song_key = ? AND tone_key = ? AND provider_id = ?",
+                (song_key, tone_key, provider_id),
+            ).fetchone()
+            if row is None:
+                raise ValueError("failed to create audio-effects mapping")
+            mapping_id = int(row[0])
+            if data.get("active") is True:
+                self.conn.execute(
+                    """
+                    INSERT INTO audio_effect_active_mappings (song_key, tone_key, mapping_id, updated_at)
+                    VALUES (?, ?, ?, datetime('now'))
+                    ON CONFLICT(song_key, tone_key) DO UPDATE SET
+                        mapping_id=excluded.mapping_id,
+                        updated_at=datetime('now')
+                    """,
+                    (song_key, tone_key, mapping_id),
+                )
+            self.conn.commit()
+        return self.get(mapping_id)
+
+    def delete(self, mapping_id: int, *, provider_id: str = "") -> bool:
+        mapping_id = self._mapping_id(mapping_id)
+        if mapping_id is None:
+            return False
+        provider_id = self._text(provider_id, field="provider_id", limit=96, allow_empty=True)
+        with self._lock:
+            if provider_id:
+                cur = self.conn.execute(
+                    "DELETE FROM audio_effect_mappings WHERE id = ? AND provider_id = ?",
+                    (mapping_id, provider_id),
+                )
+            else:
+                cur = self.conn.execute("DELETE FROM audio_effect_mappings WHERE id = ?", (mapping_id,))
+            self.conn.commit()
+            return cur.rowcount > 0
+
+    def activate(self, mapping_id: int, *, provider_id: str = "") -> dict | None:
+        mapping_id = self._mapping_id(mapping_id)
+        if mapping_id is None:
+            return None
+        provider_id = self._text(provider_id, field="provider_id", limit=96, allow_empty=True)
+        with self._lock:
+            row = self.conn.execute(
+                self._select_sql() + " WHERE m.id = ?",
+                (mapping_id,),
+            ).fetchone()
+            mapping = self._row(row)
+            if not mapping or (provider_id and mapping["provider_id"] != provider_id):
+                return None
+            self.conn.execute(
+                """
+                INSERT INTO audio_effect_active_mappings (song_key, tone_key, mapping_id, updated_at)
+                VALUES (?, ?, ?, datetime('now'))
+                ON CONFLICT(song_key, tone_key) DO UPDATE SET
+                    mapping_id=excluded.mapping_id,
+                    updated_at=datetime('now')
+                """,
+                (mapping["song_key"], mapping["tone_key"], mapping_id),
+            )
+            self.conn.commit()
+            selected = self.conn.execute(self._select_sql() + " WHERE m.id = ?", (mapping_id,)).fetchone()
+        return self._row(selected)
+
+    def clear_active(self, *, song_key: str, tone_key: str) -> bool:
+        song_key = self._text(song_key, field="song_key", limit=240)
+        tone_key = self._text(tone_key, field="tone_key", limit=160, allow_empty=True)
+        with self._lock:
+            cur = self.conn.execute(
+                "DELETE FROM audio_effect_active_mappings WHERE song_key = ? AND tone_key = ?",
+                (song_key, tone_key),
+            )
+            self.conn.commit()
+            return cur.rowcount > 0

lib/routers/__init__.py

@@ -0,0 +1,31 @@
+"""FastAPI route modules extracted from ``server.py`` (R3).
+
+Each module here exposes a module-level ``router`` (a ``fastapi.APIRouter``)
+that ``server.py`` mounts with ``app.include_router(...)`` at the point in the
+file where those routes used to be defined — FastAPI matches routes in
+registration order, so keeping the mount site preserves it.
+
+**Routers must never ``import server``.** They reach core singletons through
+the injected seam instead::
+
+    import appstate
+
+    @router.get("/api/thing")
+    def get_thing():
+        return appstate.meta_db.thing()
+
+and always as a **module attribute, at call time** — never
+``from appstate import meta_db``, which freezes the binding and defeats both a
+later ``appstate.configure()`` and ``monkeypatch.setattr``. See ``appstate.py``.
+
+Dependencies flow one way: ``server -> routers -> appstate``.
+
+**Why this lives under ``lib/``.** ``lib/`` is the only core directory every
+packaging path already copies wholesale — the Dockerfile (``COPY lib/``),
+``docker-compose.yml``, and feedback-desktop's ``bundle-slopsmith.sh``
+(``cp -r lib``) — and all three put it on ``sys.path``. A root-level package
+ships in Docker but is silently dropped from the packaged desktop app, whose
+bundler copies a hardcoded file list. Route modules import nothing at module
+scope beyond FastAPI and ``appstate``, so they do no import-time IO and satisfy
+Principle V's rule for ``lib/``.
+"""

lib/routers/audio_effects.py

@@ -0,0 +1,80 @@
+"""Audio-effects mapping API — the core-owned song/tone -> provider routing index.
+
+Extracted verbatim from ``server.py`` (R3); only the decorator receiver
+(``@app`` -> ``@router``) and the singleton read (``audio_effect_mappings`` ->
+``appstate.audio_effect_mappings``) changed. The read must stay a module
+attribute so a re-imported ``server`` re-publishes a fresh DB into the seam and
+`monkeypatch.setattr` reaches this module — see ``appstate.py``.
+"""
+
+from fastapi import APIRouter, Body, Query
+from fastapi.responses import JSONResponse
+
+import appstate
+
+router = APIRouter()
+
+
+def _audio_effects_error(exc: Exception):
+    return JSONResponse({"error": str(exc)}, status_code=400)
+
+
+@router.get("/api/audio-effects/mappings")
+def list_audio_effect_mappings(
+    song_key: str = Query(""),
+    filename: str = Query(""),
+    tone_key: str = Query(""),
+    provider_id: str = Query(""),
+):
+    try:
+        return {
+            "mappings": appstate.audio_effect_mappings.list(
+                song_key=song_key,
+                filename=filename,
+                tone_key=tone_key,
+                provider_id=provider_id,
+            )
+        }
+    except ValueError as exc:
+        return _audio_effects_error(exc)
+
+
+@router.post("/api/audio-effects/mappings")
+def upsert_audio_effect_mapping(data: dict = Body(...)):
+    try:
+        mapping = appstate.audio_effect_mappings.upsert(data)
+    except ValueError as exc:
+        return _audio_effects_error(exc)
+    return {"ok": True, "mapping": mapping}
+
+
+@router.delete("/api/audio-effects/mappings/{mapping_id}")
+def delete_audio_effect_mapping(mapping_id: int, provider_id: str = Query("")):
+    try:
+        deleted = appstate.audio_effect_mappings.delete(mapping_id, provider_id=provider_id)
+    except ValueError as exc:
+        return _audio_effects_error(exc)
+    if not deleted:
+        return JSONResponse({"error": "mapping not found"}, status_code=404)
+    return {"ok": True}
+
+
+@router.post("/api/audio-effects/mappings/{mapping_id}/activate")
+def activate_audio_effect_mapping(mapping_id: int, data: dict = Body(default_factory=dict)):
+    try:
+        provider_id = data.get("provider_id") if "provider_id" in data else data.get("providerId")
+        mapping = appstate.audio_effect_mappings.activate(mapping_id, provider_id="" if provider_id is None else provider_id)
+    except ValueError as exc:
+        return _audio_effects_error(exc)
+    if not mapping:
+        return JSONResponse({"error": "mapping not found"}, status_code=404)
+    return {"ok": True, "mapping": mapping}
+
+
+@router.delete("/api/audio-effects/active-mapping")
+def clear_audio_effect_active_mapping(song_key: str = Query(...), tone_key: str = Query("")):
+    try:
+        cleared = appstate.audio_effect_mappings.clear_active(song_key=song_key, tone_key=tone_key)
+    except ValueError as exc:
+        return _audio_effects_error(exc)
+    return {"ok": True, "cleared": cleared}

server.py

@@ -21,7 +21,7 @@ configure_logging()
 
 log = logging.getLogger("feedBack.server")
 
-from fastapi import Body, FastAPI, WebSocket, WebSocketDisconnect, UploadFile, File, HTTPException, Query
+from fastapi import Body, FastAPI, WebSocket, WebSocketDisconnect, UploadFile, File, HTTPException
 from fastapi.concurrency import run_in_threadpool
 from fastapi.staticfiles import StaticFiles
 from fastapi.responses import FileResponse, JSONResponse, RedirectResponse, Response, StreamingResponse
@@ -63,6 +63,15 @@ from metadata_db import (
     _tuning_group_key_sql,
     next_library_cursor,
 )
+# The audio-effect routing index. Same shape as metadata_db: the class lives in
+# its own module, the `audio_effect_mappings` singleton below stays here.
+from audio_effects_db import AudioEffectsMappingDB
+# The router seam. Imported as a module (never `from appstate import ...`) so
+# `appstate.configure(...)` below publishes into the same namespace routers read.
+# Lives in lib/ because that is the one core dir every packaging path copies.
+import appstate
+# Extracted route modules. They import `appstate`, never `server` — one-way graph.
+from routers import audio_effects
 import sloppak as sloppak_mod
 import drums as drums_mod
 import notation as notation_mod
@@ -347,283 +356,17 @@ def _env_flag(name: str) -> bool:
 _TUNING_GROUP_KEY_SQL = _tuning_group_key_sql("songs")
 
 
-class AudioEffectsMappingDB:
-    """Core-owned public song/tone -> provider mapping index.
-
-    Providers own the preset/chain rows addressed by provider_ref. Core owns
-    the cross-provider routing index and the active mapping per song/tone.
-    """
-
-    def __init__(self):
-        CONFIG_DIR.mkdir(parents=True, exist_ok=True)
-        self.db_path = str(CONFIG_DIR / "audio_effects.db")
-        self.conn = sqlite3.connect(self.db_path, check_same_thread=False)
-        self.conn.execute("PRAGMA journal_mode=WAL")
-        self.conn.execute("PRAGMA foreign_keys=ON")
-        self.conn.execute("""
-            CREATE TABLE IF NOT EXISTS audio_effect_mappings (
-                id INTEGER PRIMARY KEY AUTOINCREMENT,
-                song_key TEXT NOT NULL,
-                filename TEXT NOT NULL DEFAULT '',
-                tone_key TEXT NOT NULL,
-                provider_id TEXT NOT NULL,
-                provider_ref TEXT NOT NULL,
-                label TEXT NOT NULL DEFAULT '',
-                source TEXT NOT NULL DEFAULT 'manual',
-                metadata_json TEXT NOT NULL DEFAULT '{}',
-                created_at TEXT NOT NULL DEFAULT (datetime('now')),
-                updated_at TEXT NOT NULL DEFAULT (datetime('now')),
-                UNIQUE(song_key, tone_key, provider_id)
-            )
-        """)
-        self.conn.execute("""
-            CREATE TABLE IF NOT EXISTS audio_effect_active_mappings (
-                song_key TEXT NOT NULL,
-                tone_key TEXT NOT NULL,
-                mapping_id INTEGER NOT NULL,
-                updated_at TEXT NOT NULL DEFAULT (datetime('now')),
-                PRIMARY KEY (song_key, tone_key),
-                FOREIGN KEY (mapping_id) REFERENCES audio_effect_mappings(id) ON DELETE CASCADE
-            )
-        """)
-        self.conn.execute(
-            "CREATE INDEX IF NOT EXISTS idx_audio_effect_mappings_provider "
-            "ON audio_effect_mappings(provider_id)"
-        )
-        self.conn.execute(
-            "CREATE INDEX IF NOT EXISTS idx_audio_effect_mappings_filename "
-            "ON audio_effect_mappings(filename)"
-        )
-        self.conn.commit()
-        self._lock = threading.Lock()
-
-    @staticmethod
-    def _text(value, *, field: str, limit: int, allow_empty: bool = False) -> str:
-        if value is None:
-            text = ""
-        elif not isinstance(value, str):
-            raise ValueError(f"{field} must be a string")
-        else:
-            text = value.strip()
-        if not text and not allow_empty:
-            raise ValueError(f"{field} is required")
-        if len(text) > limit:
-            raise ValueError(f"{field} is too long")
-        return text
-
-    @staticmethod
-    def _mapping_id(value) -> int | None:
-        # Bind only values SQLite can store as an INTEGER; an out-of-range id is a
-        # clean miss (404), not a 500 at bind time.
-        if isinstance(value, int) and not isinstance(value, bool) and -(2 ** 63) <= value < 2 ** 63:
-            return value
-        return None
-
-    @staticmethod
-    def _field(data: dict, *keys):
-        # Select the first present snake/camel alias by key, not by truthiness, so a
-        # falsey non-string value (false/0) still reaches _text() and is rejected
-        # instead of being silently swallowed by an `or` chain.
-        for key in keys:
-            if key in data:
-                return data[key]
-        return None
-
-    @staticmethod
-    def _metadata(value) -> str:
-        if value is None:
-            return "{}"
-        if not isinstance(value, dict):
-            raise ValueError("metadata must be an object")
-        encoded = json.dumps(value, ensure_ascii=True, sort_keys=True)
-        if len(encoded) > 8192:
-            raise ValueError("metadata is too large")
-        return encoded
-
-    @staticmethod
-    def _row(row) -> dict | None:
-        if row is None:
-            return None
-        metadata = {}
-        try:
-            metadata = json.loads(row[8]) if row[8] else {}
-        except Exception:
-            metadata = {}
-        return {
-            "id": int(row[0]),
-            "song_key": row[1],
-            "filename": row[2] or "",
-            "tone_key": row[3],
-            "provider_id": row[4],
-            "provider_ref": row[5],
-            "label": row[6] or "",
-            "source": row[7] or "manual",
-            "metadata": metadata if isinstance(metadata, dict) else {},
-            "created_at": row[9] or "",
-            "updated_at": row[10] or "",
-            "active": bool(row[11]),
-        }
-
-    def _select_sql(self) -> str:
-        return """
-            SELECT m.id, m.song_key, m.filename, m.tone_key, m.provider_id,
-                   m.provider_ref, m.label, m.source, m.metadata_json,
-                   m.created_at, m.updated_at,
-                   CASE WHEN a.mapping_id IS NULL THEN 0 ELSE 1 END AS active
-            FROM audio_effect_mappings m
-            LEFT JOIN audio_effect_active_mappings a
-              ON a.song_key = m.song_key AND a.tone_key = m.tone_key AND a.mapping_id = m.id
-        """
-
-    def list(self, *, song_key: str = "", filename: str = "", tone_key: str = "", provider_id: str = "") -> list[dict]:
-        clauses: list[str] = []
-        params: list[str] = []
-        song_key = self._text(song_key, field="song_key", limit=240, allow_empty=True)
-        filename = self._text(filename, field="filename", limit=500, allow_empty=True)
-        tone_key = self._text(tone_key, field="tone_key", limit=160, allow_empty=True)
-        provider_id = self._text(provider_id, field="provider_id", limit=96, allow_empty=True)
-        if song_key and filename:
-            clauses.append("(m.song_key = ? OR m.filename = ?)")
-            params.extend([song_key, filename])
-        elif song_key:
-            clauses.append("m.song_key = ?")
-            params.append(song_key)
-        elif filename:
-            clauses.append("(m.song_key = ? OR m.filename = ?)")
-            params.extend([filename, filename])
-        if tone_key:
-            clauses.append("m.tone_key = ?")
-            params.append(tone_key)
-        if provider_id:
-            clauses.append("m.provider_id = ?")
-            params.append(provider_id)
-        sql = self._select_sql()
-        if clauses:
-            sql += " WHERE " + " AND ".join(clauses)
-        sql += " ORDER BY m.song_key COLLATE NOCASE, m.tone_key COLLATE NOCASE, m.provider_id COLLATE NOCASE"
-        with self._lock:
-            rows = self.conn.execute(sql, params).fetchall()
-        return [self._row(row) for row in rows]
-
-    def get(self, mapping_id: int) -> dict | None:
-        mapping_id = self._mapping_id(mapping_id)
-        if mapping_id is None:
-            return None
-        with self._lock:
-            row = self.conn.execute(self._select_sql() + " WHERE m.id = ?", (mapping_id,)).fetchone()
-        return self._row(row)
-
-    def upsert(self, data: dict) -> dict:
-        if not isinstance(data, dict):
-            raise ValueError("mapping body must be an object")
-        filename = self._text(data.get("filename", ""), field="filename", limit=500, allow_empty=True)
-        song_key_raw = self._field(data, "song_key", "songKey")
-        if song_key_raw is None or song_key_raw == "":
-            song_key_raw = filename
-        song_key = self._text(song_key_raw, field="song_key", limit=240)
-        tone_key = self._text(self._field(data, "tone_key", "toneKey"), field="tone_key", limit=160, allow_empty=True)
-        provider_id = self._text(self._field(data, "provider_id", "providerId"), field="provider_id", limit=96)
-        provider_ref = self._text(self._field(data, "provider_ref", "providerRef"), field="provider_ref", limit=240)
-        label = self._text(data.get("label", ""), field="label", limit=160, allow_empty=True)
-        source = self._text(data.get("source", "manual"), field="source", limit=40, allow_empty=True) or "manual"
-        metadata_json = self._metadata(data.get("metadata", {}))
-        with self._lock:
-            self.conn.execute(
-                """
-                INSERT INTO audio_effect_mappings
-                    (song_key, filename, tone_key, provider_id, provider_ref, label, source, metadata_json, updated_at)
-                VALUES (?, ?, ?, ?, ?, ?, ?, ?, datetime('now'))
-                ON CONFLICT(song_key, tone_key, provider_id) DO UPDATE SET
-                    -- Only overwrite filename when a non-empty one was supplied; an
-                    -- omitted/empty filename must preserve the stored value (it's an
-                    -- alternate lookup key for list(..., filename=...)).
-                    filename=CASE WHEN excluded.filename <> '' THEN excluded.filename ELSE audio_effect_mappings.filename END,
-                    provider_ref=excluded.provider_ref,
-                    label=excluded.label,
-                    source=excluded.source,
-                    metadata_json=excluded.metadata_json,
-                    updated_at=datetime('now')
-                """,
-                (song_key, filename, tone_key, provider_id, provider_ref, label, source, metadata_json),
-            )
-            row = self.conn.execute(
-                "SELECT id FROM audio_effect_mappings WHERE song_key = ? AND tone_key = ? AND provider_id = ?",
-                (song_key, tone_key, provider_id),
-            ).fetchone()
-            if row is None:
-                raise ValueError("failed to create audio-effects mapping")
-            mapping_id = int(row[0])
-            if data.get("active") is True:
-                self.conn.execute(
-                    """
-                    INSERT INTO audio_effect_active_mappings (song_key, tone_key, mapping_id, updated_at)
-                    VALUES (?, ?, ?, datetime('now'))
-                    ON CONFLICT(song_key, tone_key) DO UPDATE SET
-                        mapping_id=excluded.mapping_id,
-                        updated_at=datetime('now')
-                    """,
-                    (song_key, tone_key, mapping_id),
-                )
-            self.conn.commit()
-        return self.get(mapping_id)
-
-    def delete(self, mapping_id: int, *, provider_id: str = "") -> bool:
-        mapping_id = self._mapping_id(mapping_id)
-        if mapping_id is None:
-            return False
-        provider_id = self._text(provider_id, field="provider_id", limit=96, allow_empty=True)
-        with self._lock:
-            if provider_id:
-                cur = self.conn.execute(
-                    "DELETE FROM audio_effect_mappings WHERE id = ? AND provider_id = ?",
-                    (mapping_id, provider_id),
-                )
-            else:
-                cur = self.conn.execute("DELETE FROM audio_effect_mappings WHERE id = ?", (mapping_id,))
-            self.conn.commit()
-            return cur.rowcount > 0
-
-    def activate(self, mapping_id: int, *, provider_id: str = "") -> dict | None:
-        mapping_id = self._mapping_id(mapping_id)
-        if mapping_id is None:
-            return None
-        provider_id = self._text(provider_id, field="provider_id", limit=96, allow_empty=True)
-        with self._lock:
-            row = self.conn.execute(
-                self._select_sql() + " WHERE m.id = ?",
-                (mapping_id,),
-            ).fetchone()
-            mapping = self._row(row)
-            if not mapping or (provider_id and mapping["provider_id"] != provider_id):
-                return None
-            self.conn.execute(
-                """
-                INSERT INTO audio_effect_active_mappings (song_key, tone_key, mapping_id, updated_at)
-                VALUES (?, ?, ?, datetime('now'))
-                ON CONFLICT(song_key, tone_key) DO UPDATE SET
-                    mapping_id=excluded.mapping_id,
-                    updated_at=datetime('now')
-                """,
-                (mapping["song_key"], mapping["tone_key"], mapping_id),
-            )
-            self.conn.commit()
-            selected = self.conn.execute(self._select_sql() + " WHERE m.id = ?", (mapping_id,)).fetchone()
-        return self._row(selected)
-
-    def clear_active(self, *, song_key: str, tone_key: str) -> bool:
-        song_key = self._text(song_key, field="song_key", limit=240)
-        tone_key = self._text(tone_key, field="tone_key", limit=160, allow_empty=True)
-        with self._lock:
-            cur = self.conn.execute(
-                "DELETE FROM audio_effect_active_mappings WHERE song_key = ? AND tone_key = ?",
-                (song_key, tone_key),
-            )
-            self.conn.commit()
-            return cur.rowcount > 0
-
-
 meta_db = MetadataDB(CONFIG_DIR)
-audio_effect_mappings = AudioEffectsMappingDB()
+audio_effect_mappings = AudioEffectsMappingDB(CONFIG_DIR)
+
+# Publish the singletons to the router seam. server.py stays their owner — a
+# `sys.modules.pop("server")` + re-import must keep rebuilding them under a
+# patched CONFIG_DIR — and `routers/` read them back as `appstate.<name>` at
+# call time. See appstate.py for why the reads must be late-bound.
+appstate.configure(
+    meta_db=meta_db,
+    audio_effect_mappings=audio_effect_mappings,
+)
 
 
 class LocalLibraryProvider:
@@ -6251,70 +5994,9 @@ def delete_loop(loop_id: int):
 
 
 # ── Audio Effects Mapping API ───────────────────────────────────────────────
-
-def _audio_effects_error(exc: Exception):
-    return JSONResponse({"error": str(exc)}, status_code=400)
-
-
-@app.get("/api/audio-effects/mappings")
-def list_audio_effect_mappings(
-    song_key: str = Query(""),
-    filename: str = Query(""),
-    tone_key: str = Query(""),
-    provider_id: str = Query(""),
-):
-    try:
-        return {
-            "mappings": audio_effect_mappings.list(
-                song_key=song_key,
-                filename=filename,
-                tone_key=tone_key,
-                provider_id=provider_id,
-            )
-        }
-    except ValueError as exc:
-        return _audio_effects_error(exc)
-
-
-@app.post("/api/audio-effects/mappings")
-def upsert_audio_effect_mapping(data: dict = Body(...)):
-    try:
-        mapping = audio_effect_mappings.upsert(data)
-    except ValueError as exc:
-        return _audio_effects_error(exc)
-    return {"ok": True, "mapping": mapping}
-
-
-@app.delete("/api/audio-effects/mappings/{mapping_id}")
-def delete_audio_effect_mapping(mapping_id: int, provider_id: str = Query("")):
-    try:
-        deleted = audio_effect_mappings.delete(mapping_id, provider_id=provider_id)
-    except ValueError as exc:
-        return _audio_effects_error(exc)
-    if not deleted:
-        return JSONResponse({"error": "mapping not found"}, status_code=404)
-    return {"ok": True}
-
-
-@app.post("/api/audio-effects/mappings/{mapping_id}/activate")
-def activate_audio_effect_mapping(mapping_id: int, data: dict = Body(default_factory=dict)):
-    try:
-        provider_id = data.get("provider_id") if "provider_id" in data else data.get("providerId")
-        mapping = audio_effect_mappings.activate(mapping_id, provider_id="" if provider_id is None else provider_id)
-    except ValueError as exc:
-        return _audio_effects_error(exc)
-    if not mapping:
-        return JSONResponse({"error": "mapping not found"}, status_code=404)
-    return {"ok": True, "mapping": mapping}
-
-
-@app.delete("/api/audio-effects/active-mapping")
-def clear_audio_effect_active_mapping(song_key: str = Query(...), tone_key: str = Query("")):
-    try:
-        cleared = audio_effect_mappings.clear_active(song_key=song_key, tone_key=tone_key)
-    except ValueError as exc:
-        return _audio_effects_error(exc)
-    return {"ok": True, "cleared": cleared}
+# Mounted here, where these routes used to be defined: FastAPI matches in
+# registration order, so the mount site preserves it.
+app.include_router(audio_effects.router)
 
 
 # ── Settings API ──────────────────────────────────────────────────────────────

tests/test_appstate.py

@@ -0,0 +1,153 @@
+"""The router seam (`appstate.py`).
+
+The load-bearing assertion here is `test_server_wires_the_seam`: that `server`
+actually calls `appstate.configure(...)`. Every other test in this file would
+pass just fine against a seam nothing ever wires up — the same class of silent
+no-op that bit the frontend refactor twice when a scripted `setHostHooks` edit
+stopped matching its anchor. Unit tests cannot see wiring unless you make them
+look at it.
+"""
+
+import importlib
+import sys
+
+import pytest
+
+import appstate
+
+
+def _close_server_dbs(mod):
+    conn = getattr(getattr(mod, "meta_db", None), "conn", None)
+    if conn is not None:
+        getattr(mod, "_join_background_db_threads", lambda: None)()
+        conn.close()
+    ae_conn = getattr(getattr(mod, "audio_effect_mappings", None), "conn", None)
+    if ae_conn is not None:
+        ae_conn.close()
+
+
+@pytest.fixture()
+def isolated_server(tmp_path, monkeypatch):
+    """A freshly imported `server` bound to a throwaway CONFIG_DIR.
+
+    Importing `server` constructs `MetadataDB` + `AudioEffectsMappingDB` at
+    module level, so it MUST be re-imported under a patched CONFIG_DIR — an
+    unguarded `import server` would create/mutate the developer's real
+    `~/.local/share/feedback` databases. Same idiom as the other ~49
+    server-importing suites.
+
+    Teardown restores the appstate slots as well as closing the connections:
+    leaving `appstate.meta_db` published but pointing at a closed sqlite handle
+    would hand a later test (or router) a live-looking, dead singleton.
+    """
+    previous = (appstate.meta_db, appstate.audio_effect_mappings)
+    monkeypatch.setenv("CONFIG_DIR", str(tmp_path))
+    sys.modules.pop("server", None)
+    mod = importlib.import_module("server")
+    yield mod
+    _close_server_dbs(mod)
+    # Leave no half-torn-down `server` behind: the next fixture re-imports it.
+    sys.modules.pop("server", None)
+    appstate.configure(meta_db=previous[0], audio_effect_mappings=previous[1])
+
+
+def test_import_is_side_effect_free():
+    """`import appstate` must construct nothing and touch no disk.
+
+    This is why the ~49 fixtures that `sys.modules.pop("server")` and re-import
+    (to rebuild `meta_db` under a patched CONFIG_DIR) keep working untouched:
+    server owns construction, appstate only mirrors it. A singleton *owned*
+    here would survive that pop and go stale.
+    """
+    sys.modules.pop("appstate", None)
+    fresh = importlib.import_module("appstate")
+    try:
+        assert fresh.meta_db is None
+        assert fresh.audio_effect_mappings is None
+    finally:
+        sys.modules["appstate"] = appstate
+
+
+def test_configure_publishes_known_slots():
+    sentinel = object()
+    original = appstate.meta_db
+    try:
+        appstate.configure(meta_db=sentinel)
+        assert appstate.meta_db is sentinel
+    finally:
+        appstate.configure(meta_db=original)
+
+
+def test_configure_is_idempotent():
+    """server re-imports call configure() again; the last write must win."""
+    original = appstate.meta_db
+    try:
+        appstate.configure(meta_db="first")
+        appstate.configure(meta_db="second")
+        assert appstate.meta_db == "second"
+    finally:
+        appstate.configure(meta_db=original)
+
+
+def test_configure_rejects_an_unknown_slot():
+    """A typo'd or stale keyword must raise, not silently create a global that
+    nothing reads. A seam whose wiring can no-op undetected is worse than none."""
+    with pytest.raises(TypeError, match="unknown slot"):
+        appstate.configure(met_db="typo")
+    assert not hasattr(appstate, "met_db")
+
+
+def test_late_bound_read_sees_a_later_configure():
+    """Routers must read `appstate.meta_db`, never `from appstate import meta_db`.
+    This pins the property that makes that rule work."""
+    def router_style_read():
+        return appstate.meta_db          # module attribute, resolved at call time
+
+    original = appstate.meta_db
+    try:
+        appstate.configure(meta_db="before")
+        assert router_style_read() == "before"
+        appstate.configure(meta_db="after")
+        assert router_style_read() == "after"
+    finally:
+        appstate.configure(meta_db=original)
+
+
+def test_server_wires_the_seam(isolated_server):
+    """The one that catches a dropped `appstate.configure(...)` call.
+
+    Identity, not truthiness, so a stray re-assignment or a half-applied edit
+    fails here rather than in some router months later.
+    """
+    assert appstate.meta_db is isolated_server.meta_db
+    assert appstate.audio_effect_mappings is isolated_server.audio_effect_mappings
+    assert appstate.meta_db is not None
+
+
+def test_reimporting_server_republishes_the_fresh_singletons(
+    isolated_server, tmp_path, monkeypatch
+):
+    """The 49-fixture contract, exercised end to end.
+
+    Those fixtures `sys.modules.pop("server")` + re-import to rebuild `meta_db`
+    under a new CONFIG_DIR, and know nothing about appstate. So the seam must
+    re-publish on that second import. This is the test that would fail if
+    `appstate` ever *owned* the singletons: a module-level `meta_db` there
+    survives the pop and the assertions below would still see the FIRST DB.
+    """
+    first_db = isolated_server.meta_db
+    assert appstate.meta_db is first_db
+    assert str(tmp_path) in first_db.db_path
+
+    second_config = tmp_path / "second"
+    monkeypatch.setenv("CONFIG_DIR", str(second_config))
+    sys.modules.pop("server", None)
+    second_server = importlib.import_module("server")
+    try:
+        assert second_server.meta_db is not first_db          # genuinely rebuilt
+        assert str(second_config) in second_server.meta_db.db_path
+        assert appstate.meta_db is second_server.meta_db      # ...and re-published
+        assert appstate.audio_effect_mappings is second_server.audio_effect_mappings
+    finally:
+        _close_server_dbs(second_server)
+        sys.modules.pop("server", None)

tests/test_packaging.py

@@ -0,0 +1,112 @@
+"""Guard: every first-party module `server.py` imports must be one the packagers copy.
+
+feedback-desktop's `scripts/bundle-slopsmith.sh` copies a **hardcoded list** from
+core into the app bundle — `server.py`, `VERSION`, `lib/`, `data/`, `static/`,
+`plugins/__init__.py`. A new root-level module (say `appstate.py`) ships fine in
+Docker, imports fine under pytest, and is then *silently dropped* from the
+packaged desktop app, which dies at startup with:
+
+    File ".../Resources/slopsmith/server.py", line 71, in <module>
+        import appstate
+    ModuleNotFoundError: No module named 'appstate'
+
+That shipped once. This test is why it can't ship twice: it walks `server.py`'s
+module-level imports, keeps the ones that resolve inside this repo, and asserts
+each lives under a directory every packaging path already copies wholesale.
+
+If you add a first-party module for `server.py`, put it in `lib/` — the one core
+directory the Dockerfile (`COPY lib/`), `docker-compose.yml`, and the desktop
+bundler (`cp -r lib`) all copy, and that all three put on `sys.path`. If you
+genuinely need it at the repo root, you must also teach `bundle-slopsmith.sh`,
+the `Dockerfile`, `.dockerignore`, and `docker-compose.yml` about it — and then
+update `BUNDLED_ROOTS` below.
+"""
+
+import ast
+import importlib.util
+import pathlib
+
+import pytest
+
+REPO_ROOT = pathlib.Path(__file__).resolve().parent.parent
+
+# Directories every packaging path copies wholesale, plus the files copied by name.
+BUNDLED_ROOTS = ("lib", "plugins", "data", "static")
+BUNDLED_FILES = ("server.py", "main.py")
+
+
+def _server_toplevel_imports():
+    """Module names imported at `server.py`'s top level (not inside a function)."""
+    tree = ast.parse((REPO_ROOT / "server.py").read_text())
+    names = set()
+    for node in tree.body:                      # top level only — lazy imports are fine
+        if isinstance(node, ast.Import):
+            names.update(a.name.split(".")[0] for a in node.names)
+        elif isinstance(node, ast.ImportFrom) and node.level == 0 and node.module:
+            names.add(node.module.split(".")[0])
+    return sorted(names)
+
+
+# `spec.origin` is not always a path: built-in and frozen stdlib modules use
+# these sentinels. `Path("frozen").resolve()` would land inside the repo and
+# report `os` as first-party — so filter them before touching the filesystem.
+_NON_PATH_ORIGINS = {"built-in", "frozen", "namespace"}
+
+
+def _first_party_origin(name):
+    """Path of `name` if it resolves inside this repo, else None (stdlib/site-package)."""
+    try:
+        spec = importlib.util.find_spec(name)
+    except (ImportError, ValueError):
+        return None
+    if spec is None:
+        return None
+
+    if spec.origin and spec.origin not in _NON_PATH_ORIGINS:
+        origin = pathlib.Path(spec.origin)
+    else:
+        # Namespace/frozen: fall back to the first search location, if any.
+        locations = list(getattr(spec, "submodule_search_locations", None) or [])
+        if not locations:
+            return None
+        origin = pathlib.Path(locations[0])
+
+    if not origin.is_absolute():
+        return None                              # a sentinel, not a real path
+    origin = origin.resolve()
+    try:
+        origin.relative_to(REPO_ROOT)
+    except ValueError:
+        return None                              # outside the repo → a dependency
+    return origin
+
+
+@pytest.mark.parametrize("name", _server_toplevel_imports())
+def test_server_import_is_bundled(name):
+    origin = _first_party_origin(name)
+    if origin is None:
+        return                                   # stdlib or an installed dependency
+
+    rel = origin.relative_to(REPO_ROOT)
+    if rel.as_posix() in BUNDLED_FILES or rel.parts[0] in BUNDLED_ROOTS:
+        return
+
+    raise AssertionError(
+        f"server.py imports `{name}` from {rel}, which no packager copies.\n"
+        f"The desktop bundler (scripts/bundle-slopsmith.sh) copies only "
+        f"{BUNDLED_FILES} and {BUNDLED_ROOTS}/, so the packaged app would die "
+        f"at startup with ModuleNotFoundError: No module named '{name}'.\n"
+        f"Move it under lib/, or teach bundle-slopsmith.sh + Dockerfile + "
+        f".dockerignore + docker-compose.yml about it and update BUNDLED_ROOTS."
+    )
+
+
+def test_the_seam_and_routers_live_under_lib():
+    """Pin the two that already caused a shipped break."""
+    for name in ("appstate", "routers"):
+        origin = _first_party_origin(name)
+        assert origin is not None, f"{name} does not resolve inside the repo"
+        assert origin.relative_to(REPO_ROOT).parts[0] == "lib", (
+            f"{name} resolved to {origin.relative_to(REPO_ROOT)}; it must live "
+            f"under lib/ or the packaged desktop app will not ship it"
+        )