feat: Implement Windows runner for Flutter application

- Added FlutterWindow class to manage the Flutter view within a Win32 window.
- Created main entry point in main.cpp to initialize and run the Flutter application.
- Implemented utility functions for console attachment and command line argument parsing.
- Added resource management for application icon and manifest.
- Enhanced Win32Window class for DPI awareness and theme management.
- Included necessary headers and resource files for building the Windows runner.

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
+  }
+}