Support Headless WebView Module (WASM Bridge)

[kunihir0]

This tracks the Swift host implementation for WebView support. This is required to allow plugins to bypass Cloudflare challenges and execute site-specific obfuscated JS.

Required tasks:

• Define ItoWebviewModule protocol in HostModules.swift.
• Bind ito:core/webview FFI inside WasmBridge.swift.
• Provide bridging mechanisms so the main iOS app can safely execute WKWebView tasks on the Main Thread and return the data to the background WASM execution.

Depends on itoapp/ito-rs#1