Rework song player view to match design system

- New split layout: waveform/transport/queue left, comment panel right
- Avatar pins above waveform positioned by timestamp with hover tooltips
- Transport bar: speed selector, ±30s skip, 46px amber play/pause, volume
- Comment compose: live timestamp pill, suggestion/issue/keeper tag buttons
- Comment list: per-author colour avatars, amber timestamp seek chips,
  playhead-proximity highlight, delete only shown on own comments
- Queue panel showing other songs in the same session
- Waveform colours updated to amber/dim palette (104px height)
- Add GET /songs/{song_id} endpoint for song metadata
- Add tag field to SongComment (model, schema, router, migration 0005)
- Fix migration 0005 down_revision to use short ID "0004"
- Fix ESLint no-unused-expressions in keyboard shortcut handler

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

api/src/rehearsalhub/db/models.py

@@ -207,6 +207,7 @@ class SongComment(Base):
     )
     body: Mapped[str] = mapped_column(Text, nullable=False)
     timestamp: Mapped[Optional[float]] = mapped_column(Numeric(10, 2), nullable=True)
+    tag: Mapped[Optional[str]] = mapped_column(String(32), nullable=True)
     created_at: Mapped[datetime] = mapped_column(
         DateTime(timezone=True), server_default=func.now(), nullable=False
     )

api/src/rehearsalhub/routers/songs.py

@@ -89,6 +89,24 @@ async def search_songs(
     ]
 
 
+@router.get("/songs/{song_id}", response_model=SongRead)
+async def get_song(
+    song_id: uuid.UUID,
+    session: AsyncSession = Depends(get_session),
+    current_member: Member = Depends(get_current_member),
+):
+    song_repo = SongRepository(session)
+    song = await song_repo.get_with_versions(song_id)
+    if song is None:
+        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Song not found")
+    band_svc = BandService(session)
+    try:
+        await band_svc.assert_membership(song.band_id, current_member.id)
+    except PermissionError:
+        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="Not a member")
+    return SongRead.model_validate(song).model_copy(update={"version_count": len(song.versions)})
+
+
 @router.patch("/songs/{song_id}", response_model=SongRead)
 async def update_song(
     song_id: uuid.UUID,
@@ -264,7 +282,7 @@ async def create_comment(
 ):
     await _assert_song_membership(song_id, current_member.id, session)
     repo = CommentRepository(session)
-    comment = await repo.create(song_id=song_id, author_id=current_member.id, body=data.body, timestamp=data.timestamp)
+    comment = await repo.create(song_id=song_id, author_id=current_member.id, body=data.body, timestamp=data.timestamp, tag=data.tag)
     comment = await repo.get_with_author(comment.id)
     return SongCommentRead.from_model(comment)
 

api/src/rehearsalhub/schemas/comment.py

@@ -9,6 +9,7 @@ from pydantic import BaseModel, ConfigDict
 class SongCommentCreate(BaseModel):
     body: str
     timestamp: float | None = None
+    tag: str | None = None
 
 
 class SongCommentRead(BaseModel):
@@ -21,6 +22,7 @@ class SongCommentRead(BaseModel):
     author_name: str
     author_avatar_url: str | None
     timestamp: float | None
+    tag: str | None
     created_at: datetime
 
     @classmethod
@@ -33,5 +35,6 @@ class SongCommentRead(BaseModel):
             author_name=getattr(getattr(c, "author"), "display_name"),
             author_avatar_url=getattr(getattr(c, "author"), "avatar_url"),
             timestamp=getattr(c, "timestamp"),
+            tag=getattr(c, "tag", None),
             created_at=getattr(c, "created_at"),
         )