Canvas: fix A2UI click actions

apps/macos/Sources/Clawdis/DeepLinks.swift

@@ -12,6 +12,11 @@ final class DeepLinkHandler {
 
     private var lastPromptAt: Date = .distantPast
 
+    // Ephemeral, in-memory key used for unattended deep links originating from the in-app Canvas.
+    // This avoids blocking Canvas init on UserDefaults and doesn't weaken the external deep-link prompt:
+    // outside callers can't know this randomly generated key.
+    private nonisolated static let canvasUnattendedKey: String = DeepLinkHandler.generateRandomKey()
+
     func handle(url: URL) async {
         guard let route = DeepLinkParser.parse(url) else {
             deepLinkLogger.debug("ignored url \(url.absoluteString, privacy: .public)")
@@ -35,7 +40,7 @@ final class DeepLinkHandler {
             return
         }
 
-        let allowUnattended = link.key == Self.expectedKey()
+        let allowUnattended = link.key == Self.canvasUnattendedKey || link.key == Self.expectedKey()
         if !allowUnattended {
             if Date().timeIntervalSince(self.lastPromptAt) < 1.0 {
                 deepLinkLogger.debug("throttling deep link prompt")
@@ -83,6 +88,10 @@ final class DeepLinkHandler {
         self.expectedKey()
     }
 
+    static func currentCanvasKey() -> String {
+        self.canvasUnattendedKey
+    }
+
     private static func expectedKey() -> String {
         let defaults = UserDefaults.standard
         if let key = defaults.string(forKey: deepLinkKeyKey), !key.isEmpty {
@@ -100,6 +109,17 @@ final class DeepLinkHandler {
         return key
     }
 
+    private nonisolated static func generateRandomKey() -> String {
+        var bytes = [UInt8](repeating: 0, count: 32)
+        _ = SecRandomCopyBytes(kSecRandomDefault, bytes.count, &bytes)
+        let data = Data(bytes)
+        return data
+            .base64EncodedString()
+            .replacingOccurrences(of: "+", with: "-")
+            .replacingOccurrences(of: "/", with: "_")
+            .replacingOccurrences(of: "=", with: "")
+    }
+
     // MARK: - UI
 
     private func confirm(title: String, message: String) -> Bool {