修复：CI 部署环境与 ref 错配、迁移碎片化、图片意图 source_span、章节物化脏版式、会话历史与本地语音不一致

新增：TTS 上传 COS 与分片、章节 reading_segments 物化与快照、markdown 清洗、会话消息 repository、语音 store 重构与相关测试

api/app/features/conversation/ws/router.py

@@ -462,11 +462,16 @@ async def websocket_endpoint(
                                     },
                                 )
 
+                                try:
+                                    ads = int(audio_duration)
+                                except (TypeError, ValueError):
+                                    ads = 0
                                 segment = Segment(
                                     id=str(uuid.uuid4()),
                                     conversation_id=conversation_id,
                                     transcript_text=transcript_text,
                                     audio_url=f"audio:{audio_duration}s",
+                                    audio_duration_seconds=ads if ads > 0 else None,
                                     processed=False,
                                 )
                                 db.add(segment)