feat: refine voice studio attention workflow

backend/app/schemas/voice_session_schemas.py

@@ -121,6 +121,7 @@ class VoiceSessionSummaryResponse(BaseModel):
     latest_safety_message: str | None = None
     latest_assistant_audio_ready: bool = False
     last_turn_status: str | None = None
+    attention_reasons: list[str] = Field(default_factory=list)
     transcription_mode_hint: str | None = None
     can_continue: bool = False
     can_finalize: bool = False
@@ -149,6 +150,10 @@ class VoiceSessionAnalyticsResponse(BaseModel):
 
     window_days: int | None = None
     total_sessions: int = 0
+    attention_sessions: int = 0
+    confirmation_attention_sessions: int = 0
+    safety_attention_sessions: int = 0
+    failed_attention_sessions: int = 0
     active_sessions: int = 0
     finalized_sessions: int = 0
     abandoned_sessions: int = 0