feat: refine voice studio attention workflow

backend/app/api/voice_sessions.py

@@ -1,5 +1,7 @@
 """Voice co-creation session APIs."""
 
+from typing import Literal
+
 from fastapi import (
     APIRouter,
     Depends,
@@ -82,6 +84,10 @@ async def list_voice_sessions(
         le=settings.voice_session_max_list_limit,
     ),
     active_only: bool = Query(default=False),
+    needs_attention: bool = Query(default=False),
+    attention_reason: (
+        Literal["pending_confirmation", "safety_intervention", "failed_turn"] | None
+    ) = Query(default=None),
     active_first: bool = Query(default=True),
     user: User = Depends(require_user),
     db: AsyncSession = Depends(get_db),
@@ -92,6 +98,8 @@ async def list_voice_sessions(
         db,
         limit=limit,
         active_only=active_only,
+        needs_attention=needs_attention,
+        attention_reason=attention_reason,
         active_first=active_first,
     )