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/tests/features/voice/use-player.test.tsx

@@ -0,0 +1,50 @@
+import { renderHook } from '@testing-library/react-native';
+
+import { usePlayer } from '@/features/voice/hooks/use-player';
+
+const mockUseAudioPlayer = jest.fn();
+const mockUseAudioPlayerStatus = jest.fn();
+
+jest.mock('expo-audio', () => ({
+  useAudioPlayer: (...args: unknown[]) => mockUseAudioPlayer(...args),
+  useAudioPlayerStatus: (...args: unknown[]) =>
+    mockUseAudioPlayerStatus(...args),
+}));
+
+jest.mock('@/core/audio/audio-focus', () => ({
+  audioFocus: {
+    acquireForPlayback: jest.fn(),
+    releaseIfOwnedBy: jest.fn(),
+    onOwnerChange: jest.fn(() => jest.fn()),
+  },
+}));
+
+describe('usePlayer', () => {
+  beforeEach(() => {
+    mockUseAudioPlayer.mockReset();
+    mockUseAudioPlayerStatus.mockReset();
+
+    mockUseAudioPlayer.mockReturnValue({
+      pause: jest.fn(),
+      play: jest.fn(),
+    });
+    mockUseAudioPlayerStatus.mockReturnValue({
+      isLoaded: false,
+      playing: false,
+      currentTime: 0,
+      duration: 0,
+    });
+  });
+
+  test('keeps the native audio session active while app-level audio focus owns teardown', () => {
+    renderHook(() => usePlayer());
+
+    expect(mockUseAudioPlayer).toHaveBeenCalledWith(
+      null,
+      expect.objectContaining({
+        downloadFirst: false,
+        keepAudioSessionActive: true,
+      }),
+    );
+  });
+});