feat: band NC folder config, fix watcher event filter, add light/dark theme

- Add PATCH /bands/{id} endpoint for admins to update nc_folder_path
- Add band NC scan folder UI panel with inline edit
- Fix watcher: use activity type field (not human-readable subject) for upload detection
- Reorder watcher filters: audio extension check first, then band path, then type
- Add dark/light theme toggle using GitHub Primer-inspired CSS custom properties
- All inline styles migrated to CSS variables for theme-awareness

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

api/src/rehearsalhub/routers/bands.py

@@ -6,7 +6,8 @@ from sqlalchemy.ext.asyncio import AsyncSession
 from rehearsalhub.db.engine import get_session
 from rehearsalhub.db.models import Member
 from rehearsalhub.dependencies import get_current_member
-from rehearsalhub.schemas.band import BandCreate, BandRead, BandReadWithMembers
+from rehearsalhub.schemas.band import BandCreate, BandRead, BandReadWithMembers, BandUpdate
+from rehearsalhub.repositories.band import BandRepository
 from rehearsalhub.services.band import BandService
 
 router = APIRouter(prefix="/bands", tags=["bands"])
@@ -17,7 +18,6 @@ async def list_bands(
     session: AsyncSession = Depends(get_session),
     current_member: Member = Depends(get_current_member),
 ):
-    from rehearsalhub.repositories.band import BandRepository
     repo = BandRepository(session)
     bands = await repo.list_for_member(current_member.id)
     return [BandRead.model_validate(b) for b in bands]
@@ -53,3 +53,29 @@ async def get_band(
     if band is None:
         raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Band not found")
     return BandReadWithMembers.model_validate(band)
+
+
+@router.patch("/{band_id}", response_model=BandRead)
+async def update_band(
+    band_id: uuid.UUID,
+    data: BandUpdate,
+    session: AsyncSession = Depends(get_session),
+    current_member: Member = Depends(get_current_member),
+):
+    repo = BandRepository(session)
+    role = await repo.get_member_role(band_id, current_member.id)
+    if role != "admin":
+        raise HTTPException(status_code=status.HTTP_403_FORBIDDEN, detail="Admin only")
+
+    band = await repo.get_by_id(band_id)
+    if band is None:
+        raise HTTPException(status_code=status.HTTP_404_NOT_FOUND, detail="Band not found")
+
+    updates: dict = {}
+    if data.nc_folder_path is not None:
+        path = data.nc_folder_path.strip()
+        updates["nc_folder_path"] = (path.rstrip("/") + "/") if path else None
+
+    if updates:
+        band = await repo.update(band, **updates)
+    return BandRead.model_validate(band)

api/src/rehearsalhub/schemas/band.py

@@ -21,6 +21,10 @@ class BandCreate(BaseModel):
     nc_base_path: str | None = None  # e.g. "Bands/MyBand/" — defaults to "bands/{slug}/"
 
 
+class BandUpdate(BaseModel):
+    nc_folder_path: str | None = None  # update the Nextcloud base folder for scans
+
+
 class BandRead(BaseModel):
     model_config = ConfigDict(from_attributes=True)
     id: uuid.UUID