fix(node,hub): key music/media metadata lookups by file_id, not path

IndexEntry.path is the *folder* a file is in (indexer.py's
_virtual_dir docstring: "the directory a file appears in"), not the
file itself. GroupIndex.get_entry_by_path() treated it as if it named
one file, and every one of its four callers did too:
_do_music_meta_request, _do_media_meta_request, _do_tmdb_override, and
_admin_exec_tmdb_override. Any two files sharing a folder — an album is
one folder with many tracks, a season is one folder with many episodes
— collided: a lookup by path silently returned whichever entry the
index happened to iterate to first, regardless of which file the
client actually asked about.

Found live (2026-08-25): three unrelated albums ("High Tone - Various",
two "Le Peuple de l'Herbe" albums) all showed the same MusicBrainz
cover, because all their representative tracks happened to sit in one
"high_tone" folder alongside a track that legitimately matched that
cover. A force-reload didn't help — the bug is server-side, not a
stale client state.

Fixed by keying these four request/response pairs by `file_id` (the
entry's own content hash — already unique, already how every other
lookup in the system identifies a file) instead of `path`, both in the
wire messages (music_meta_req/resp, media_meta_req/resp, tmdb_override)
and in music-app.js/video-app.js's own hooks. GroupIndex.get_entry_by_path
is now unused and removed — GroupIndex.get_entry(file_id) already did
the right thing.

No test previously exercised either handler with two entries sharing a
folder — the only existing coverage (test_tmdb_override_policy.py) gave
each entry its own folder, so the bug never had a chance to show up.
Added that scenario there and in two new test files, all confirmed
failing against the pre-fix code before being confirmed green against
the fix.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013XSohfUQQiaE77qyFLgSv3

1 files changed, 38 insertions, 11 deletions

diff --git a/packages/meshbay-node/tests/test_tmdb_override_policy.py b/packages/meshbay-node/tests/test_tmdb_override_policy.py
index b8fa6f9..cd1cee1 100644
--- a/packages/meshbay-node/tests/test_tmdb_override_policy.py
+++ b/packages/meshbay-node/tests/test_tmdb_override_policy.py
@@ -65,7 +65,7 @@ def _entry(path: str, name: str, display_title: str) -> IndexEntry:
 
 # ── Refused before a challenge is even issued ───────────────────────────────
 
-async def test_missing_path_is_refused(tmp_path):
+async def test_missing_file_id_is_refused(tmp_path):
     session = _session(tmp_path, "op", operator="op")
     session._has_admin_authority = lambda: True
     issued = []
@@ -79,24 +79,25 @@ async def test_missing_path_is_refused(tmp_path):
 
 async def test_missing_tmdb_id_is_refused(tmp_path):
     session = _session(tmp_path, "op", operator="op")
-    session._ctx["index"].add_entry(_entry("shared", "ep.mkv", "Show"))
+    entry = _entry("shared", "ep.mkv", "Show")
+    session._ctx["index"].add_entry(entry)
     session._has_admin_authority = lambda: True
     issued = []
     session._issue_admin_challenge = lambda op, subject: issued.append((op, subject))
 
-    session._do_tmdb_override({"path": "shared", "media_type": "tv"})
+    session._do_tmdb_override({"file_id": entry.id, "media_type": "tv"})
 
     assert not issued
     assert [m for m in session.sent if m.get("type") == "error"]
 
 
-async def test_unknown_path_is_refused(tmp_path):
+async def test_unknown_file_id_is_refused(tmp_path):
     session = _session(tmp_path, "op", operator="op")
     session._has_admin_authority = lambda: True
     issued = []
     session._issue_admin_challenge = lambda op, subject: issued.append((op, subject))
 
-    session._do_tmdb_override({"path": "nope", "tmdb_id": "123", "media_type": "tv"})
+    session._do_tmdb_override({"file_id": "nope", "tmdb_id": "123", "media_type": "tv"})
 
     assert not issued
     assert [m for m in session.sent if m.get("type") == "error"]
@@ -104,25 +105,51 @@ async def test_unknown_path_is_refused(tmp_path):
 
 async def test_a_request_with_nobody_to_authorize_it_is_refused(tmp_path):
     session = _session(tmp_path, "member-1", operator="the-operator")
-    session._ctx["index"].add_entry(_entry("shared", "ep.mkv", "Show"))
+    entry = _entry("shared", "ep.mkv", "Show")
+    session._ctx["index"].add_entry(entry)
     session._has_admin_authority = lambda: False
 
-    session._do_tmdb_override({"path": "shared", "tmdb_id": "123", "media_type": "tv"})
+    session._do_tmdb_override({"file_id": entry.id, "tmdb_id": "123", "media_type": "tv"})
 
     assert [m for m in session.sent if m.get("type") == "error"]
 
 
 async def test_a_valid_request_is_signed(tmp_path):
     session = _session(tmp_path, "op", operator="op")
-    session._ctx["index"].add_entry(_entry("shared", "ep.mkv", "War of the Worlds"))
+    entry = _entry("shared", "ep.mkv", "War of the Worlds")
+    session._ctx["index"].add_entry(entry)
     session._has_admin_authority = lambda: True
     issued = []
     session._issue_admin_challenge = lambda op, subject: issued.append((op, subject))
 
-    session._do_tmdb_override({"path": "shared", "tmdb_id": "2255", "media_type": "tv"})
+    session._do_tmdb_override({"file_id": entry.id, "tmdb_id": "2255", "media_type": "tv"})
 
     assert issued == [(OP_TMDB_OVERRIDE,
-                       "path=shared,tmdb_id=2255,media_type=tv")]
+                       f"file_id={entry.id},tmdb_id=2255,media_type=tv")]
+
+
+async def test_two_files_in_the_same_folder_are_told_apart(tmp_path):
+    """
+    Regression (found live, 2026-08-25): `IndexEntry.path` is the *folder* a
+    file is in, not the file itself — two files in the same folder (any
+    multi-episode season) used to collide when looked up by path, silently
+    resolving to whichever entry the index happened to return first. Keyed
+    by `file_id` now, so two entries sharing a folder must resolve to their
+    own, distinct entries.
+    """
+    session = _session(tmp_path, "op", operator="op")
+    e1 = _entry("shared/Season 1", "s01e01.mkv", "War of the Worlds")
+    e2 = _entry("shared/Season 1", "s01e02.mkv", "War of the Worlds")
+    session._ctx["index"].add_entry(e1)
+    session._ctx["index"].add_entry(e2)
+    session._has_admin_authority = lambda: True
+    issued = []
+    session._issue_admin_challenge = lambda op, subject: issued.append((op, subject))
+
+    session._do_tmdb_override({"file_id": e2.id, "tmdb_id": "2255", "media_type": "tv"})
+
+    assert issued == [(OP_TMDB_OVERRIDE,
+                       f"file_id={e2.id},tmdb_id=2255,media_type=tv")]
 
 
 # ── Applying the override ───────────────────────────────────────────────────
@@ -151,7 +178,7 @@ async def test_override_updates_every_entry_sharing_the_display_title(tmp_path):
         session._peer_registry = lambda: {"peer-1": peer}
 
         await session._admin_exec_tmdb_override(
-            {"subject": "path=shared/S1,tmdb_id=999,media_type=tv"},
+            {"subject": f"file_id={s1.id},tmdb_id=999,media_type=tv"},
             b"transcript", b"sig")
 
         for e in (s1, s2, s3):