feat: C3 客户端埋点 SDK（EventTracker 批量上报 + 核心事件）

lib/core/data/services/event_tracker.dart

@@ -0,0 +1,64 @@
+// Author: fruit.com.cn
+
+import 'dart:async';
+
+import 'api_client.dart';
+
+/// 核心埋点事件名（第一阶段口径，后续与运营对齐后可扩展）。
+class AppEvents {
+  AppEvents._();
+
+  static const String playbackStart = 'playback_start';
+  static const String playbackEnd = 'playback_end';
+  static const String paySuccess = 'pay_success';
+  static const String register = 'register';
+  static const String click = 'click';
+}
+
+/// 埋点上报：本地缓冲、批量上报，失败静默丢弃不影响主流程。
+class EventTracker {
+  EventTracker(this._api);
+
+  final ApiClient _api;
+
+  static const int _flushSize = 10;
+  static const Duration _flushInterval = Duration(seconds: 10);
+
+  final List<Map<String, Object?>> _buffer = [];
+  Timer? _timer;
+
+  void track(
+    String eventName, {
+    String? page,
+    Map<String, Object?>? properties,
+  }) {
+    _buffer.add({
+      'eventName': eventName,
+      'eventTime': DateTime.now().toIso8601String(),
+      'page': page,
+      'properties': properties,
+    });
+    if (_buffer.length >= _flushSize) {
+      flush();
+    } else {
+      _timer ??= Timer(_flushInterval, flush);
+    }
+  }
+
+  Future<void> flush() async {
+    if (_buffer.isEmpty) return;
+    final events = List<Map<String, Object?>>.from(_buffer);
+    _buffer.clear();
+    _timer?.cancel();
+    _timer = null;
+    try {
+      await _api.post('/app/events', data: {
+        'deviceId': 'device-0001',
+        'sessionId': 'session-0001',
+        'events': events,
+      });
+    } catch (_) {
+      // 埋点失败不影响主流程，静默丢弃。
+    }
+  }
+}