build(client/ios): B1 完成——PacketTunnel 链接 libbox+系统框架,iOS 构建打通

- PacketTunnel 链 Libbox.xcframework(静态,只Link不Embed)+ NetworkExtension
  + SystemConfiguration + libresolv.tbd + UIKit(libbox iOS 引用 UIApplication);
  OTHER_LDFLAGS="" 切 CocoaPods 继承,FRAMEWORK_SEARCH_PATHS 指 Frameworks/
- 桥接头手动声明 sockaddr_ctl/ctl_info(iOS SDK 无 kern_control.h,稳定内核 ABI)
- 部署目标 iOS 12→14(os.Logger 需 14;低版老机不再兼容,用户拍板)
- 修预存脚手架坑: Podfile 删悬空 RunnerTests; Info.plist 移出 Resources(双产出);
  Runner 构建阶段重排(Embed App Extensions 前置, Thin Binary 殿后) 解依赖环
- 验证: flutter build ios 通过, C1 Provider 编译通过, otool -L 扩展零外部 @rpath

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

client/ios/Podfile

@@ -1,5 +1,5 @@
 # Uncomment this line to define a global platform for your project
-platform :ios, '12.0'
+platform :ios, '14.0'
 
 # CocoaPods analytics sends network stats synchronously affecting flutter build latency.
 ENV['COCOAPODS_DISABLE_STATS'] = 'true'
@@ -32,9 +32,6 @@ target 'Runner' do
   use_modular_headers!
 
   flutter_install_all_ios_pods File.dirname(File.realpath(__FILE__))
-  target 'RunnerTests' do
-    inherit! :search_paths
-  end
 end
 
 post_install do |installer|