feat: V13 — per-card "re-match this one file" (MNP 0.13)

A one-click alternative to the full "Fix match" search-and-pick flow, and
reachable without SSH (`meshbay-node video rematch` clears a whole group).

- MNP 0.13: tmdb_rematch / tmdb_rematch_ack (additive — an older node
  logs "unknown type", the button just does nothing). OP_TMDB_REMATCH,
  signed like tmdb_override (media_cache is shared node-wide).
- media_cache.drop_tmdb_match(file_id): forgets the match AND the
  override marker — deliberately stronger than clear_file_tmdb, since the
  operator is explicitly asking for a fresh resolution.
- webrtc_server: _do_tmdb_rematch / _admin_exec_tmdb_rematch, dispatch +
  admin-response routing, broadcasts tmdb_rematch_ack.
- transport.js: rematchTmdbMatch(fileId, signFn); 'tmdb_rematch' in the
  admin-op allowlist; tmdb_rematch_ack handled like tmdb_override_ack.
- video-app.js: a "Re-match" button beside "Fix match" in the detail
  modal (isNodeAdmin), then bumpMediaMetaGeneration(). video.rematch_one
  key in all ten locales.

docs/mediacenter.md §10.1: V8–V13 marked done.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_018BMLQjqFGCize2KtNBT79v

1 files changed, 12 insertions, 0 deletions

diff --git a/packages/meshbay-node/src/meshbay_node/media_cache.py b/packages/meshbay-node/src/meshbay_node/media_cache.py
index 4600a09..8233270 100644
--- a/packages/meshbay-node/src/meshbay_node/media_cache.py
+++ b/packages/meshbay-node/src/meshbay_node/media_cache.py
@@ -175,6 +175,18 @@ class MediaCache:
             "(SELECT file_id FROM tmdb_override)", (file_id,))
         await self._db.commit()
 
+    async def drop_tmdb_match(self, file_id: str) -> None:
+        """
+        Full per-file reset: forget the match *and* any manual override
+        marker, so the next `media_meta_req` re-resolves from scratch with
+        the current matcher. This is the explicit operator "re-match this
+        one" action (§10.1/V13) — deliberately stronger than
+        `clear_file_tmdb`, which spares an override.
+        """
+        await self._db.execute("DELETE FROM file_tmdb WHERE file_id = ?", (file_id,))
+        await self._db.execute("DELETE FROM tmdb_override WHERE file_id = ?", (file_id,))
+        await self._db.commit()
+
     async def clear_tmdb_matches(self, file_ids: list[str]) -> int:
         """
         Drop the auto-resolved file->tmdb mappings for these files so the