Fix NameError in versions.py

- Fixed undefined 'song' and 'role' variables in stream_version
- Now properly gets song and role from _get_version_and_assert_band_membership
- Debug logging will now work correctly

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

api/src/rehearsalhub/routers/versions.py

@@ -227,7 +227,8 @@ async def stream_version(
     session: AsyncSession = Depends(get_session),
     current_member: Member = Depends(_member_from_request),
 ):
-    version, _ = await _get_version_and_assert_band_membership(version_id, session, current_member)
+    version, song = await _get_version_and_assert_band_membership(version_id, session, current_member)
+    role = await BandRepository(session).get_member_role(song.band_id, current_member.id)
 
     # Debug logging for permission issues
     import logging