macos: hook up our new update controller

macos/Sources/Features/Update/UpdateController.swift

@@ -0,0 +1,55 @@
+import Sparkle
+import Cocoa
+
+/// Standard controller for managing Sparkle updates in Ghostty.
+///
+/// This controller wraps SPUStandardUpdaterController to provide a simpler interface
+/// for managing updates with Ghostty's custom driver and delegate. It handles
+/// initialization, starting the updater, and provides the check for updates action.
+class UpdateController {
+    private(set) var updater: SPUUpdater
+    private let userDriver: UpdateDriver
+    private let updaterDelegate = UpdaterDelegate()
+    
+    var viewModel: UpdateViewModel {
+        userDriver.viewModel
+    }
+    
+    /// Initialize a new update controller.
+    init() {
+        let hostBundle = Bundle.main
+        self.userDriver = UpdateDriver(viewModel: .init())
+        self.updater = SPUUpdater(
+            hostBundle: hostBundle,
+            applicationBundle: hostBundle,
+            userDriver: userDriver,
+            delegate: updaterDelegate
+        )
+    }
+    
+    /// Start the updater.
+    ///
+    /// This must be called before the updater can check for updates. If starting fails,
+    /// an error alert will be shown after a short delay.
+    func startUpdater() {
+        try? updater.start()
+    }
+    
+    /// Check for updates.
+    ///
+    /// This is typically connected to a menu item action.
+    @objc func checkForUpdates() {
+        updater.checkForUpdates()
+    }
+    
+    /// Validate the check for updates menu item.
+    ///
+    /// - Parameter item: The menu item to validate
+    /// - Returns: Whether the menu item should be enabled
+    func validateMenuItem(_ item: NSMenuItem) -> Bool {
+        if item.action == #selector(checkForUpdates) {
+            return updater.canCheckForUpdates
+        }
+        return true
+    }
+}