fix(node): make Photos/Video/Music enrichment survive node restarts

Only thumbnail bytes were ever durable in media_cache.db — every other
derived field (photo width/height/EXIF, video ffprobe duration/dims,
audio cover art) lived solely on the in-memory GroupIndex entry, so a
node restart re-decoded every photo through Pillow, re-ran ffprobe on
every video, and re-scanned for every album cover from scratch, even
though the answers already sat in the cache.

Adds photo_meta and video_meta tables (content-only fields, keyed by
file_id) and checks them before doing the expensive work. Audio gets no
new table: mutagen reads tags and duration in one inseparable call, so
caching duration alone buys nothing — instead cover-art extraction alone
is skipped via a new skip_cover flag when a cached cover already exists.

Deliberately excluded from all three caches: anything derived from the
filename or folder path (video display_title/season/episode via guessit,
audio artist/album folder-fallback) — those must keep being recomputed
fresh so a rename/move is still correctly re-derived by the existing
_reenrich_renamed_*_entries mechanisms, instead of silently handing back
a stale parse under the new name/location.

Regression tests prove cache reuse by deleting the source file (or cover)
between two enrichment runs, and prove rename/move correctness survives
the new cache by renaming/moving to a path that never exists on disk.

1 files changed, 85 insertions, 4 deletions

diff --git a/packages/meshbay-node/src/meshbay_node/media_cache.py b/packages/meshbay-node/src/meshbay_node/media_cache.py
index 47032b8..63cda41 100644
--- a/packages/meshbay-node/src/meshbay_node/media_cache.py
+++ b/packages/meshbay-node/src/meshbay_node/media_cache.py
@@ -54,6 +54,24 @@ CREATE TABLE IF NOT EXISTS season_meta (
     fetched_at  REAL NOT NULL,
     PRIMARY KEY (tmdb_id, season)
 );
+-- Videos app: the ffprobe fields enrich.py derives alongside the
+-- thumbnail — duration/width/height only, deliberately *not*
+-- display_title/season/episode. Those come from guessit against the
+-- filename, which is exactly what a rename needs re-derived
+-- (_reenrich_renamed_video_entries exists for precisely that); caching
+-- them here would silently defeat that mechanism by handing back the old
+-- name's parse under the new name. ffprobe's own output has no such
+-- concern — the same bytes probe the same regardless of what the file is
+-- called — so only the content-only fields are safe to skip recomputing.
+-- thumb_hash is not duplicated here either, for the same reason it isn't
+-- in photo_meta — get_thumb_hash_by_file_id(file_id) already answers that,
+-- and it too is content-only (a frame grab doesn't depend on the name).
+CREATE TABLE IF NOT EXISTS video_meta (
+    file_id       TEXT PRIMARY KEY,
+    duration      INTEGER,
+    width         INTEGER,
+    height        INTEGER
+);
 CREATE TABLE IF NOT EXISTS file_mbid (
     file_id     TEXT PRIMARY KEY,
     mbid        TEXT NOT NULL
@@ -63,6 +81,21 @@ CREATE TABLE IF NOT EXISTS mbid_meta (
     json        TEXT NOT NULL,
     fetched_at  REAL NOT NULL
 );
+-- Photos app (docs/photos.md): the technical/EXIF fields enrich_photo.py
+-- reads alongside the thumbnail. Durable for the same reason `thumbs` is —
+-- without this, only the thumbnail bytes survived a restart, and every
+-- image was still fully re-decoded through Pillow just to re-derive
+-- width/height/taken_at/camera, which get_thumb_hash_by_file_id's own
+-- cache hit had already proven unnecessary. thumb_hash is not duplicated
+-- here — get_thumb_hash_by_file_id(file_id) already answers that, and a
+-- second copy would just be one more place for the two to drift.
+CREATE TABLE IF NOT EXISTS photo_meta (
+    file_id     TEXT PRIMARY KEY,
+    width       INTEGER,
+    height      INTEGER,
+    taken_at    INTEGER,
+    camera      TEXT
+);
 """
 
 # TMDB overviews/ratings do drift; a file's own resolved tmdb_id does not
@@ -231,17 +264,65 @@ class MediaCache:
         )
         await self._db.commit()
 
+    # ── photo technical/EXIF fields (Photos app) ─────────────────────────────
+
+    async def get_photo_meta(self, file_id: str) -> dict | None:
+        async with self._db.execute(
+            "SELECT width, height, taken_at, camera FROM photo_meta WHERE file_id = ?",
+            (file_id,),
+        ) as cur:
+            row = await cur.fetchone()
+        if not row:
+            return None
+        return {"width": row[0], "height": row[1], "taken_at": row[2], "camera": row[3]}
+
+    async def put_photo_meta(self, file_id: str, width: int | None, height: int | None,
+                             taken_at: int | None, camera: str | None) -> None:
+        await self._db.execute(
+            "INSERT OR REPLACE INTO photo_meta (file_id, width, height, taken_at, camera) "
+            "VALUES (?, ?, ?, ?, ?)",
+            (file_id, width, height, taken_at, camera),
+        )
+        await self._db.commit()
+
+    # ── video technical fields (Videos app) ──────────────────────────────────
+    #
+    # duration/width/height only — see the schema comment on why
+    # display_title/season/episode are deliberately not cached here.
+
+    async def get_video_meta(self, file_id: str) -> dict | None:
+        async with self._db.execute(
+            "SELECT duration, width, height FROM video_meta WHERE file_id = ?",
+            (file_id,),
+        ) as cur:
+            row = await cur.fetchone()
+        if not row:
+            return None
+        return {"duration": row[0], "width": row[1], "height": row[2]}
+
+    async def put_video_meta(self, file_id: str, duration: int | None,
+                             width: int | None, height: int | None) -> None:
+        await self._db.execute(
+            "INSERT OR REPLACE INTO video_meta (file_id, duration, width, height) "
+            "VALUES (?, ?, ?, ?)",
+            (file_id, duration, width, height),
+        )
+        await self._db.commit()
+
     # ── pruning ───────────────────────────────────────────────────────────────
 
     async def prune_file(self, file_id: str) -> None:
         """
         Called when a file leaves the index (deletion, unshared root). Removes
-        its thumbnail and its file->tmdb/file->mbid mappings. `tmdb_meta`/
-        `mbid_meta` rows are left alone — they're keyed by tmdb_id/mbid, not
-        file_id, and other files (other episodes of the same show, other
-        tracks of the same release) may still reference the same entry.
+        its thumbnail, its per-app technical fields, and its file->tmdb/
+        file->mbid mappings. `tmdb_meta`/`mbid_meta` rows are left alone —
+        they're keyed by tmdb_id/mbid, not file_id, and other files (other
+        episodes of the same show, other tracks of the same release) may
+        still reference the same entry.
         """
         await self._db.execute("DELETE FROM thumbs WHERE file_id = ?", (file_id,))
+        await self._db.execute("DELETE FROM photo_meta WHERE file_id = ?", (file_id,))
+        await self._db.execute("DELETE FROM video_meta WHERE file_id = ?", (file_id,))
         await self._db.execute("DELETE FROM file_tmdb WHERE file_id = ?", (file_id,))
         await self._db.execute("DELETE FROM file_mbid WHERE file_id = ?", (file_id,))
         await self._db.commit()