feat: MeshCore SAR - Flutter BLE mesh radio companion app

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

macos/Runner/AppDelegate.swift

@@ -0,0 +1,13 @@
+import Cocoa
+import FlutterMacOS
+
+@main
+class AppDelegate: FlutterAppDelegate {
+  override func applicationShouldTerminateAfterLastWindowClosed(_ sender: NSApplication) -> Bool {
+    return true
+  }
+
+  override func applicationSupportsSecureRestorableState(_ app: NSApplication) -> Bool {
+    return true
+  }
+}