fix(conversation): 修复实时会话 TTS/回复被离屏 WS 抢占

- 列表预热仅预取消息缓存，避免后台 WebSocket 覆盖服务端连接
- RealtimeSession UI 回调按 owner 独占，防止 offscreen 覆盖聊天页
- 列表页聚焦时再 prewarm，会话页 TTS 入队优先 base64
- 管线下发 TTS 同时带 audio_base64 与 audio_url；协议说明同步
- 移除 TTS 排查用前后端调试日志，保留错误/告警
- 补充 WS / RealtimeSession / entry-warmup / 播放器相关单测

Co-authored-by: Cursor <cursoragent@cursor.com>

app-expo/tests/core/ws/client.test.ts

@@ -118,6 +118,45 @@ describe('WsClient', () => {
     client.dispose();
   });
 
+  test('maps tts audio with base64 and url playback channels', async () => {
+    const client = new WsClient('conv-123');
+    const events: WsEvent[] = [];
+    client.onEvent((e) => events.push(e));
+
+    await client.connect();
+    await new Promise((r) => setTimeout(r, 10));
+
+    const ws = (client as unknown as { ws: MockWebSocket }).ws;
+    ws.simulateMessage({
+      type: 'tts_audio',
+      conversation_id: 'conv-123',
+      data: {
+        audio_base64: 'ZmFrZS1tcDM=',
+        audio_url: 'https://example.com/tts.mp3',
+        index: 0,
+        total: 1,
+        assistant_message_id: 'aa11aa11-aaaa-aaaa-aaaa-aaaaaaaaaaaa',
+        manual: true,
+      },
+      timestamp: '2026-01-01T00:00:00Z',
+    });
+
+    expect(events).toEqual([
+      {
+        kind: 'tts_audio_received',
+        conversationId: 'conv-123',
+        audioBase64: 'ZmFrZS1tcDM=',
+        audioUrl: 'https://example.com/tts.mp3',
+        index: 0,
+        total: 1,
+        assistantMessageId: 'aa11aa11-aaaa-aaaa-aaaa-aaaaaaaaaaaa',
+        manual: true,
+      },
+    ]);
+
+    client.dispose();
+  });
+
   test('sends text messages', async () => {
     const client = new WsClient('conv-123');