Fix NameError: BandRepository not defined

- Added import for BandRepository in stream_version function
- Import at function level to avoid circular import issues
- Now debug logging will work correctly

Generated by Mistral Vibe.
Co-Authored-By: Mistral Vibe <vibe@mistral.ai>

api/src/rehearsalhub/routers/versions.py

@@ -228,6 +228,9 @@ async def stream_version(
     current_member: Member = Depends(_member_from_request),
 ):
     version, song = await _get_version_and_assert_band_membership(version_id, session, current_member)
+    
+    # Import at function level to avoid circular imports
+    from rehearsalhub.repositories.band import BandRepository
     role = await BandRepository(session).get_member_role(song.band_id, current_member.id)
 
     # Debug logging for permission issues