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/network/mock/dio_mock_adapter.dart

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+import 'dart:async';
+import 'dart:convert';
+import 'dart:typed_data';
+
+import 'package:dio/dio.dart';
+import 'package:sunny_mochi/core/config/api_paths.dart';
+import 'package:sunny_mochi/core/config/env.dart' show Env;
+import 'package:sunny_mochi/core/network/mock/mock_response_loader.dart';
+import 'package:sunny_mochi/core/observability/talker_setup.dart';
+
+/// 把 Dio 请求拦截，根据 path + method 返回 fixtures 中的预设响应。
+///
+/// 启用方式：在 dio_client.dart 中检查 [Env.useMock]：
+/// ```dart
+/// if (Env.useMock) {
+///   dio.httpClientAdapter = buildDefaultMockAdapter();
+/// }
+/// ```
+class DioMockAdapter implements HttpClientAdapter {
+  DioMockAdapter({this.delay = const Duration(milliseconds: 200)});
+
+  final Map<String, String> _routes = {};
+  final Duration delay;
+  bool _closed = false;
+
+  /// 注册一条 mock 路由：method+path → fixtures 文件名（不含 .json 后缀）。
+  void register(String method, String path, String fixtureName) {
+    _routes['${method.toUpperCase()} $path'] = fixtureName;
+  }
+
+  @override
+  void close({bool force = false}) {
+    _closed = true;
+  }
+
+  @override
+  Future<ResponseBody> fetch(
+    RequestOptions options,
+    Stream<Uint8List>? requestStream,
+    Future<void>? cancelFuture,
+  ) async {
+    if (_closed) {
+      throw DioException(requestOptions: options, message: 'adapter closed');
+    }
+
+    await Future<void>.delayed(delay);
+
+    final key = '${options.method} ${options.path}';
+    final exact = _routes[key];
+    var matched = exact;
+    if (matched == null) {
+      for (final entry in _routes.entries) {
+        if (key.startsWith(entry.key)) {
+          matched = entry.value;
+          break;
+        }
+      }
+    }
+
+    if (matched == null) {
+      appTalker.warning('[Mock] 未注册 fixture：$key — 返回空 envelope');
+      final body = jsonEncode({
+        'code': '00000',
+        'msg': 'mock-empty',
+        'data': null,
+      });
+      return ResponseBody.fromString(
+        body,
+        200,
+        headers: {'content-type': ['application/json']},
+      );
+    }
+
+    appTalker.verbose('[Mock] $key → fixtures/$matched.json');
+    final json = await MockResponseLoader.load(matched);
+    final body = jsonEncode(json);
+    return ResponseBody.fromString(
+      body,
+      200,
+      headers: {'content-type': ['application/json']},
+    );
+  }
+}
+
+/// 默认的全局 mock 路由表。
+// TODO: 按项目实际 API 路径扩展此路由表
+DioMockAdapter buildDefaultMockAdapter() {
+  return DioMockAdapter()
+    // === Auth ===
+    ..register('POST', ApiPaths.authLoginSms, 'auth/login_success')
+    ..register('POST', ApiPaths.authLoginPwd, 'auth/login_success')
+    ..register('POST', ApiPaths.authSmsSend, 'auth/send_sms_code_success')
+    ..register('POST', ApiPaths.authRefresh, 'auth/refresh_success')
+    ..register('POST', ApiPaths.crashReport, 'common/generic_success')
+    // === User / Mine ===
+    ..register('GET', ApiPaths.userProfile, 'mine/profile')
+    ..register('POST', ApiPaths.userChangePassword, 'common/generic_success')
+    ..register('POST', ApiPaths.userAvatarUpload, 'mine/avatar_upload');
+}

lib/core/network/mock/mock_response_loader.dart

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+import 'dart:convert';
+
+import 'package:flutter/services.dart' show rootBundle;
+
+/// 从 assets/fixtures/ 加载 JSON 响应。
+///
+/// 使用：
+/// ```dart
+/// final body = await MockResponseLoader.load('auth/login_success');
+/// ```
+abstract class MockResponseLoader {
+  static final Map<String, Map<String, dynamic>> _cache = {};
+
+  static Future<Map<String, dynamic>> load(String name) async {
+    if (_cache.containsKey(name)) return _cache[name]!;
+    final raw = await rootBundle.loadString('assets/fixtures/$name.json');
+    final json = jsonDecode(raw) as Map<String, dynamic>;
+    _cache[name] = json;
+    return json;
+  }
+}