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

ios/Podfile

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+# Flutter Template — iOS Podfile
+# 目标平台 iOS 15.0（v1.2 锁定，详见 docs/flutter-architecture-design.md §十一.6）
+# Q1 答复 = 接受 iOS 15 → 保持本配置；如需保 iOS 13/14，调整 platform 行后重跑 pod install。
+platform :ios, '15.0'
+
+# CocoaPods 静态链接（与腾讯 IM 三件套兼容；P4 接入 IM 时再启用）
+# 注意：use_frameworks! :linkage => :static 要求所有 Pod 支持静态库
+# ENV['COCOAPODS_DISABLE_STATS'] = 'true'
+
+project 'Runner', {
+  'Debug' => :debug,
+  'Profile' => :release,
+  'Release' => :release,
+}
+
+def flutter_root
+  generated_xcode_build_settings_path = File.expand_path(File.join('..', 'Flutter', 'Generated.xcconfig'), __FILE__)
+  unless File.exist?(generated_xcode_build_settings_path)
+    raise "#{generated_xcode_build_settings_path} must exist. If you're running pod install manually, make sure flutter pub get is executed first"
+  end
+
+  File.foreach(generated_xcode_build_settings_path) do |line|
+    matches = line.match(/FLUTTER_ROOT\=(.*)/)
+    return matches[1].strip if matches
+  end
+  raise "FLUTTER_ROOT not found in #{generated_xcode_build_settings_path}. Try deleting Generated.xcconfig, then run flutter pub get"
+end
+
+require File.expand_path(File.join('packages', 'flutter_tools', 'bin', 'podhelper'), flutter_root)
+
+flutter_ios_podfile_setup
+
+target 'Runner' do
+  use_frameworks!
+
+  flutter_install_all_ios_pods File.dirname(File.realpath(__FILE__))
+  target 'RunnerTests' do
+    inherit! :search_paths
+  end
+end
+
+post_install do |installer|
+  installer.pods_project.targets.each do |target|
+    flutter_additional_ios_build_settings(target)
+    target.build_configurations.each do |config|
+      # 强制所有 Pod 的最低部署目标 ≥ iOS 15.0（与 Podfile platform 行对齐）
+      config.build_settings['IPHONEOS_DEPLOYMENT_TARGET'] = '15.0'
+    end
+  end
+end