Wire KeychainDelegate before DataManager init to fix token persistence

TokenManager.keychainDelegate was never set, so all Keychain reads/writes
failed silently. Tokens couldn't be persisted or loaded on app restart,
and TokenStorage.getToken() returned nil during task completion flows.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

iosApp/iosApp/iOSApp.swift

@@ -23,6 +23,10 @@ struct iOSApp: App {
     init() {
         UITestRuntime.configureForLaunch()
 
+        // Set Keychain delegate BEFORE DataManager.initialize() so token can be
+        // loaded from Keychain on startup (Kotlin/Native can't use SecItem* directly)
+        TokenManager.Companion.shared.keychainDelegate = KeychainHelper.shared
+
         // Initialize DataManager with platform-specific managers
         // This must be done before any other operations that access DataManager
         DataManager.shared.initialize(