fix: add WebView to view hierarchy to enable JavaScript execution

CRITICAL FIX: WKWebView on macOS requires being in the view hierarchy
to properly execute JavaScript. The WebView was created but never added
to any view, causing JavaScript (including the game-bridge callbacks) to
never execute.

Changes:
- Set webView.hidden = NO (was YES)
- Position WebView offscreen (-10000, -10000) with minimal size (1x1)
- Add WebView to main window's content view
- Add logging for debugging

This ensures JavaScript runs even though the WebView UI is not visible
to the user.

Author: rodrigo-fournier-immutable

Plugins/Mac/Sources/ImmutableWebView.mm

@@ -143,7 +143,21 @@ - (id)initWithUa:(const char *)ua
     webView = wkwebView;
     webView.UIDelegate = self;
     webView.navigationDelegate = self;
-    webView.hidden = YES;
+    
+    // CRITICAL: WebView must be in view hierarchy and not hidden to execute JavaScript
+    // Even though we don't need UI, we add it offscreen to ensure JavaScript runs
+    webView.hidden = NO;
+    webView.frame = CGRectMake(-10000, -10000, 1, 1); // Position offscreen
+    
+    // Add to main window to ensure JavaScript execution
+    NSArray *windows = [[NSApplication sharedApplication] windows];
+    if ([windows count] > 0) {
+        NSWindow *mainWindow = [windows objectAtIndex:0];
+        [[mainWindow contentView] addSubview:webView];
+        NSLog(@"[ImmutableWebView] WebView added to main window for JavaScript execution");
+    } else {
+        NSLog(@"[ImmutableWebView] WARNING: No window available, WebView may not execute JavaScript");
+    }
 
     if (ua != NULL && strcmp(ua, "") != 0) {
         ((WKWebView *)webView).customUserAgent = [[NSString alloc] initWithUTF8String:ua];