feat: 饭卡打印助手 Flutter 版（Phase 1/2：协议服务器 + macOS CUPS 真机打印）

- 协议与 C# 版 card-printer-agent 逐字段对齐（38200-38202 顺延、CORS *、串行任务队列、30 分钟保留）
- macOS CUPS 后端：lpoptions 队列发现 + lp 参数列表提交（LC_ALL=C 防本地化粘连坑）
- --mock 模拟模式 + bin/agent.dart headless 入口 + 测试卡生成工具
- 真机验收：HiTi CS-200e status 就绪 + 真实出卡；macOS 通用二进制构建通过
- App Sandbox 已关闭（服务需绑回环端口并调用 lp 子进程）；zaxprint URL scheme 已注册

.metadata

@@ -0,0 +1,30 @@
+# This file tracks properties of this Flutter project.
+# Used by Flutter tool to assess capabilities and perform upgrades etc.
+#
+# This file should be version controlled and should not be manually edited.
+
+version:
+  revision: "c23637390482d4cf9598c3ce3f2be31aa7332daf"
+  channel: "stable"
+
+project_type: app
+
+# Tracks metadata for the flutter migrate command
+migration:
+  platforms:
+    - platform: root
+      create_revision: c23637390482d4cf9598c3ce3f2be31aa7332daf
+      base_revision: c23637390482d4cf9598c3ce3f2be31aa7332daf
+    - platform: macos
+      create_revision: c23637390482d4cf9598c3ce3f2be31aa7332daf
+      base_revision: c23637390482d4cf9598c3ce3f2be31aa7332daf
+
+  # User provided section
+
+  # List of Local paths (relative to this file) that should be
+  # ignored by the migrate tool.
+  #
+  # Files that are not part of the templates will be ignored by default.
+  unmanaged_files:
+    - 'lib/main.dart'
+    - 'ios/Runner.xcodeproj/project.pbxproj'