feat: 添加 Analytics 分析功能（行为追踪、错误码、协议更新）

apps/lib/features/chat/presentation/bloc/chat_bloc.dart

@@ -12,6 +12,7 @@ import 'package:social_app/core/chat/chat_list_item.dart';
 import 'package:social_app/core/chat/chat_orchestrator.dart';
 import 'package:social_app/core/chat/chat_history_repository.dart';
 import 'package:social_app/core/chat/chat_timeline_reconciler.dart';
+import 'package:social_app/core/analytics/tracker.dart';
 import 'package:social_app/core/l10n/l10n.dart';
 import 'chat_bloc_recovery_utils.dart';
 
@@ -20,6 +21,13 @@ part 'chat_bloc_send.dart';
 part 'chat_bloc_history.dart';
 part 'chat_bloc_attachments.dart';
 
+typedef ChatCompletedCallback =
+    void Function({
+      required String conversationId,
+      required int messageCount,
+      required int responseTimeMs,
+    });
+
 class ChatState implements ChatOrchestratorState {
   @override
   final List<ChatListItem> items;
@@ -115,12 +123,14 @@ class ChatBloc extends Cubit<ChatState> implements ChatOrchestrator {
     required ChatApi chatApi,
     ChatHistoryRepository? historyRepository,
     Future<void> Function()? onCalendarMutated,
+    ChatCompletedCallback? onChatCompleted,
     Duration recoveryPollInterval = const Duration(milliseconds: 700),
     Duration recoveryTimeout = const Duration(seconds: 20),
   }) : _service =
            service ??
            AgUiService(chatApi: chatApi, historyRepository: historyRepository),
        _onCalendarMutated = onCalendarMutated,
+       _onChatCompleted = onChatCompleted,
        _recoveryPollInterval = recoveryPollInterval,
        _recoveryTimeout = recoveryTimeout,
        super(const ChatState()) {
@@ -129,9 +139,14 @@ class ChatBloc extends Cubit<ChatState> implements ChatOrchestrator {
 
   final AgUiService _service;
   final Future<void> Function()? _onCalendarMutated;
+  final ChatCompletedCallback? _onChatCompleted;
   final Duration _recoveryPollInterval;
   final Duration _recoveryTimeout;
   String? _activeUserId;
+  DateTime? _activeRunStartedAt;
+  DateTime? _activeRunFirstResponseAt;
+  String? _activeRunId;
+  String? _activeThreadId;
   int _sessionEpoch = 0;
   final Map<String, Uint8List> _attachmentPreviewCache = <String, Uint8List>{};
   final Map<String, Future<Uint8List?>> _attachmentPreviewInflight =
@@ -259,4 +274,54 @@ class ChatBloc extends Cubit<ChatState> implements ChatOrchestrator {
       emit(state.copyWith(error: error.toString()));
     }
   }
+
+  void _recordRunStarted({required String runId, required String threadId}) {
+    _activeRunStartedAt = DateTime.now();
+    _activeRunFirstResponseAt = null;
+    _activeRunId = runId;
+    _activeThreadId = threadId;
+  }
+
+  void _recordRunFirstResponse() {
+    _activeRunFirstResponseAt ??= DateTime.now();
+  }
+
+  void _trackChatCompleted() {
+    final startedAt = _activeRunStartedAt;
+    if (startedAt == null) {
+      return;
+    }
+    final firstResponseAt = _activeRunFirstResponseAt ?? DateTime.now();
+    final responseTimeMs = firstResponseAt.difference(startedAt).inMilliseconds;
+    final threadId = _activeThreadId?.trim();
+    final runId = _activeRunId?.trim();
+    final conversationId = (threadId != null && threadId.isNotEmpty)
+        ? threadId
+        : runId;
+    if (conversationId == null || conversationId.isEmpty) {
+      return;
+    }
+    final onChatCompleted = _onChatCompleted;
+    if (onChatCompleted != null) {
+      onChatCompleted(
+        conversationId: conversationId,
+        messageCount: 1,
+        responseTimeMs: responseTimeMs,
+      );
+      return;
+    }
+    AnalyticsTracker.instance.trackAgentChatCompleted(
+      conversationId: conversationId,
+      scenario: 'assistant',
+      messageCount: 1,
+      responseTimeMs: responseTimeMs,
+    );
+  }
+
+  void _clearRunMetrics() {
+    _activeRunStartedAt = null;
+    _activeRunFirstResponseAt = null;
+    _activeRunId = null;
+    _activeThreadId = null;
+  }
 }

apps/lib/features/chat/presentation/bloc/chat_bloc_events.dart

@@ -6,6 +6,11 @@ extension _ChatBlocEvents on ChatBloc {
   void _handleEvent(AgUiEvent event) {
     switch (event.type) {
       case AgUiEventType.runStarted:
+        final runStartedEvent = event as RunStartedEvent;
+        _recordRunStarted(
+          runId: runStartedEvent.runId,
+          threadId: runStartedEvent.threadId,
+        );
         emit(
           state.copyWith(
             isSending: false,
@@ -17,11 +22,14 @@ extension _ChatBlocEvents on ChatBloc {
           ),
         );
       case AgUiEventType.runFinished:
+        _trackChatCompleted();
+        _clearRunMetrics();
         emit(
           _resetRunState().copyWith(items: _removeToolCallItems(state.items)),
         );
       case AgUiEventType.runError:
         final errorEvent = event as RunErrorEvent;
+        _clearRunMetrics();
         final isCanceledByUser = errorEvent.code == 'RUN_CANCELED';
         emit(
           _resetRunState(
@@ -72,6 +80,7 @@ extension _ChatBlocEvents on ChatBloc {
   }
 
   void _handleTextMessageEnd(TextMessageEndEvent event) {
+    _recordRunFirstResponse();
     final timestamp = DateTime.now();
     final items = _updateOrAddMessage(
       state.items,