feat(memory,conversation): 记忆富化/证据包、时间线幂等字段与对话分段全链路

数据库
- 新增迁移 0003：timeline_events.memory_source_id 外键 → memory_sources，便于按 ingest 源做时间线幂等

后端 - 记忆
- 新增 ingest 后 LLM 富化（摘要/事实/时间线），可配置开关与最大字符数
- 新增证据包组装：合并 chunk、摘要、事实、时间线、故事等检索结果；支持空 query 时是否仍带 rolling 等开关
- repo/retriever/service/router/schemas/summarizer/timeline/extractor 等扩展；文档 memory-retrieval.md 更新

后端 - 对话 WS
- 增加 PING/PONG；分段 ASR 日志与空音频处理；转写失败与「无助手回复」错误提示更明确
- 助手多段回复持久化使用统一分隔符，与分段逻辑一致

后端 - Agent
- reply_limits：按 [SPLIT] 与段落拆段，并保证非空 fallback，供 WS 与 TTS 多段下发

后端 - 回忆录任务
- transcript ingest 记录 source_id；任务成功结?

app-expo/src/features/voice/hooks/use-player.ts

@@ -47,7 +47,13 @@ export function usePlayer(): UsePlayerResult {
       typeof currentSource === 'string' &&
       (currentSource.startsWith('https://') ||
         currentSource.startsWith('http://'));
-    return { downloadFirst: remote };
+    return {
+      downloadFirst: remote,
+      // Expo's native player deactivates AVAudioSession on pause by default.
+      // We manage session ownership centrally via audioFocus, so keep it active
+      // until audioFocus.release() explicitly tears it down.
+      keepAudioSessionActive: true,
+    };
   }, [currentSource]);
 
   const player = useAudioPlayer(currentSource, playerOptions);
@@ -76,7 +82,7 @@ export function usePlayer(): UsePlayerResult {
         setCurrentSource(null);
         setStatus('idle');
         setQueueLength(0);
-        await audioFocus.release();
+        await audioFocus.releaseIfOwnedBy('player');
         return;
       }
 
@@ -170,7 +176,7 @@ export function usePlayer(): UsePlayerResult {
       setCurrentPlaybackItem(null);
       setCurrentSource(null);
       setStatus('idle');
-      await audioFocus.release();
+      await audioFocus.releaseIfOwnedBy('player');
       await playNext();
     },
     [player, playNext],
@@ -189,7 +195,7 @@ export function usePlayer(): UsePlayerResult {
     setCurrentPlaybackItem(null);
     setCurrentSource(null);
     setStatus('idle');
-    await audioFocus.release();
+    await audioFocus.releaseIfOwnedBy('player');
   }, [player]);
 
   return {