fix(ios): restore ScreenController.mode

apps/ios/Sources/Screen/ScreenController.swift

@@ -6,6 +6,11 @@ import WebKit
 @MainActor
 @Observable
 final class ScreenController {
+    enum Mode: Sendable {
+        case canvas
+        case web
+    }
+
     let webView: WKWebView
     private let navigationDelegate: ScreenNavigationDelegate
     private let a2uiActionHandler: CanvasA2UIActionMessageHandler
@@ -13,6 +18,10 @@ final class ScreenController {
     var urlString: String = ""
     var errorText: String?
 
+    var mode: Mode {
+        self.urlString.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty ? .canvas : .web
+    }
+
     /// Callback invoked when a clawdis:// deep link is tapped in the canvas
     var onDeepLink: ((URL) -> Void)?