fix(ios): add content src to config.xml for HTML loading

Added missing content src tag to config.xml:

Content Source:
- Added <content src="index.html" /> tag
- Tells Capacitor/Cordova which HTML file to load
- Required for WebView to display the app

Fixes:
- Black screen: WebView now knows which HTML file to load
- Missing start page: Capacitor can now find index.html
- WebView initialization: Proper content source configured

Result: WebView should now load index.html from public directory

test-apps/ios-test-app/App/App/config.xml

@@ -1,6 +1,5 @@
 <?xml version='1.0' encoding='utf-8'?>
 <widget version="1.0.0" xmlns="http://www.w3.org/ns/widgets" xmlns:cdv="http://cordova.apache.org/ns/1.0">
   <access origin="*" />
-  
+  <content src="index.html" />
-  
 </widget>