feat(conversation): TTS 投递与 WebSocket 管线；客户端播放门禁与会话页联动；COS 键与迁移脚本调整

api/app/features/conversation/service.py

@@ -19,6 +19,7 @@ from app.features.conversation.models import Conversation
 from app.features.conversation.session_history import (
     conversation_messages_to_redis_history,
 )
+from app.features.conversation.tts_delivery import apply_presigned_tts_urls_to_messages
 from app.features.memory import repo as memory_repo
 from app.features.quota.service import QuotaService
 from app.ports.storage import ObjectStorage
@@ -248,11 +249,13 @@ class ConversationService:
         conv = await self.get_or_404(conversation_id, user_id)
         try:
             history = await self.ensure_redis_history_from_db(conversation_id)
-            return _build_messages_from_history(
+            messages = _build_messages_from_history(
                 conversation_id=conversation_id,
                 history=history,
                 fallback_timestamp=conv.started_at,
             )
+            apply_presigned_tts_urls_to_messages(messages, self._object_storage)
+            return messages
         except Exception:
             return []