Replace osascript/JXA with native Mach-O agent and SMAppService to fix EDR detection

- Add CodeBurnRefreshAgent target: native fire-and-exit binary posting com.codeburn.refresh notification
- Rewrite installLaunchAgentIfNeeded(): plist ProgramArguments points to native binary, not osascript/JXA
- Rewrite registerLoginItemIfNeeded(): uses SMAppService API instead of osascript/System Events
- Add startSocketListener(): Unix domain socket for CLI-triggered menubar refresh
- Add src/menubar-socket.ts: CLI-side notifyMenubar() helper wired into status --format menubar-json
- Update Package.swift with new product/target, package-app.sh copies agent into bundle Resources
- Add tests: plist content verification, login item guard, agent smoke test

mac/Sources/CodeBurnRefreshAgent/main.swift

@@ -0,0 +1,8 @@
+import Foundation
+
+DistributedNotificationCenter.default().postNotificationName(
+    .init("com.codeburn.refresh"),
+    object: nil,
+    userInfo: nil,
+    options: .deliverImmediately
+)