chore: 初始化脚手架 — sunny_mochi 企业级 Flutter 模板

Core 基础设施：Flavor 三包体系、Drift+SQLCipher 加密数据库
7 拦截器 Dio 网络栈、CrashReporter 崩溃日志、Sealed Failure 错误体系
5 色板主题系统、Auth 认证骨架（Clean Architecture）、Dev Panel、Mock Adapter

通过验证：flutter analyze（0 errors）、flutter test（全绿）、staging APK 74.8MB

lib/core/crash/crash_datasource.dart

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+import 'package:dio/dio.dart';
+import 'package:sunny_mochi/core/config/api_paths.dart';
+import 'package:sunny_mochi/core/crash/pending_crash_report.dart';
+import 'package:sunny_mochi/core/network/api_response.dart';
+import 'package:sunny_mochi/core/network/dio_client.dart';
+import 'package:riverpod_annotation/riverpod_annotation.dart';
+
+part 'crash_datasource.g.dart';
+
+@riverpod
+CrashDatasource crashDatasource(Ref ref) =>
+    CrashDatasource(ref.watch(dioClientProvider));
+
+/// 崩溃报告上报接口。
+///
+/// **后端接口规范（待后端实现）**：
+/// ```
+/// POST /sys/crash-report
+/// Headers: satoken: <token>（可选，未登录也应接受）
+/// Body: { "kind", "error", "stackTrace", "occurredAt", "deviceModel", ... }
+/// Response: { "retCode": "00000", "retMsg": "ok", "retData": null }
+/// ```
+// TODO(backend): 实现 POST /sys/crash-report 接口（接收客户端崩溃日志）
+class CrashDatasource {
+  const CrashDatasource(this._dio);
+  final Dio _dio;
+
+  Future<void> sendCrashReport(PendingCrashReport report) async {
+    final resp = await _dio.post<Map<String, dynamic>>(
+      ApiPaths.crashReport,
+      data: report.toJson(),
+    );
+    parseEnvelope(resp.data, (j) => j).unwrapVoid();
+  }
+}