升级到 XCFramework，添加模拟器支持

- 创建支持真机和模拟器的 XCFramework
- 模拟器版本使用空壳实现，用于开发调试
- 真机版本包含完整 Unity 运行时
- 更新 podspec 版本到 1.0.7
- 移除所有架构排除配置，XCFramework 自动处理

simulator_stub/UnityFrameworkStub.m

@@ -0,0 +1,94 @@
+#import <UIKit/UIKit.h>
+#import <Foundation/Foundation.h>
+
+// Stub implementation for simulator
+typedef struct mach_header_64 MachHeader;
+
+@protocol UnityFrameworkListener<NSObject>
+@optional
+- (void)unityDidUnload:(NSNotification*)notification;
+- (void)unityDidQuit:(NSNotification*)notification;
+@end
+
+@interface UnityAppController : NSObject
+@end
+
+@implementation UnityAppController
+@end
+
+@interface UnityFramework : NSObject
+@end
+
+@implementation UnityFramework
+
++ (instancetype)getInstance {
+    static UnityFramework *instance = nil;
+    static dispatch_once_t onceToken;
+    dispatch_once(&onceToken, ^{
+        instance = [[self alloc] init];
+    });
+    return instance;
+}
+
+- (id)appController {
+    return nil;
+}
+
+- (UITextField*)keyboardTextField {
+    return nil;
+}
+
+- (void)setDataBundleId:(const char*)bundleId {
+    // Stub
+}
+
+- (void)runUIApplicationMainWithArgc:(int)argc argv:(char*[])argv {
+    // Stub
+}
+
+- (void)runEmbeddedWithArgc:(int)argc argv:(char*[])argv appLaunchOpts:(NSDictionary*)appLaunchOpts {
+    // Stub - 模拟器不运行 Unity
+    NSLog(@"UnityFramework: Simulator stub - Unity not available");
+}
+
+- (void)unloadApplication {
+    // Stub
+}
+
+- (void)quitApplication:(int)exitCode {
+    // Stub
+}
+
+- (void)registerFrameworkListener:(id)obj {
+    // Stub
+}
+
+- (void)unregisterFrameworkListener:(id)obj {
+    // Stub
+}
+
+- (void)showUnityWindow {
+    // Stub
+}
+
+- (void)pause:(bool)pause {
+    // Stub
+}
+
+- (void)setAbsoluteURL:(const char *)url {
+    // Stub
+}
+
+- (void)setExecuteHeader:(const MachHeader*)header {
+    // Stub
+}
+
+- (void)sendMessageToGOWithName:(const char*)goName functionName:(const char*)name message:(const char*)msg {
+    // Stub
+}
+
+@end
+
+// Export version symbols
+double UnityFrameworkVersionNumber = 1.0;
+const unsigned char UnityFrameworkVersionString[] = "1.0";