Make the app reachable and quittable after the panel closes

Closing the panel only hid it, and launching the app again did nothing
because the running instance ignored the reopen, so it looked like the
app refused to exit. Reopening now shows the panel, and the main menu
makes Cmd+Q and Cmd+W work while the panel has focus. Termination also
tears down the event tap, hotkeys and sync timers instead of leaving
them live.

Sources/Prompt/App.swift

@@ -47,6 +47,7 @@ final class AppDelegate: NSObject, NSApplicationDelegate {
         HotkeyManager.shared.start()
 
         setupStatusItem()
+        setupMainMenu()
 
         // Show the panel on launch so the app is discoverable (it has no Dock
         // icon and the menu bar icon can be hard to spot on a full bar).
@@ -56,6 +57,52 @@ final class AppDelegate: NSObject, NSApplicationDelegate {
         }
     }
 
+    /// A launched-again app must reveal itself. Without this, `open` (or
+    /// clicking it in Finder/Spotlight) hits the running instance, which does
+    /// nothing, so the app looks like it never started.
+    @MainActor
+    func applicationShouldHandleReopen(_ sender: NSApplication, hasVisibleWindows flag: Bool) -> Bool {
+        PanelController.shared.show()
+        return true
+    }
+
+    @MainActor
+    func applicationShouldTerminate(_ sender: NSApplication) -> NSApplication.TerminateReply {
+        // Stop the poll timer, any queued push, the event tap and the Carbon
+        // hotkeys so termination cannot be held up by a live callback.
+        SyncService.shared.stop()
+        HotkeyManager.shared.stop()
+        return .terminateNow
+    }
+
+    /// Accessory apps have no visible menu bar, but the main menu still
+    /// services key equivalents — this is what makes Cmd+Q and Cmd+W work
+    /// while the panel has focus.
+    private func setupMainMenu() {
+        let mainMenu = NSMenu()
+        let appMenuItem = NSMenuItem()
+        mainMenu.addItem(appMenuItem)
+
+        let appMenu = NSMenu()
+        appMenuItem.submenu = appMenu
+
+        let hide = NSMenuItem(title: "Hide Panel", action: #selector(hidePanel), keyEquivalent: "w")
+        hide.target = self
+        appMenu.addItem(hide)
+
+        appMenu.addItem(.separator())
+
+        let quit = NSMenuItem(title: "Quit Prompt", action: #selector(quit), keyEquivalent: "q")
+        quit.target = self
+        appMenu.addItem(quit)
+
+        NSApp.mainMenu = mainMenu
+    }
+
+    @MainActor @objc private func hidePanel() {
+        PanelController.shared.hide()
+    }
+
     private func setupStatusItem() {
         let item = NSStatusBar.system.statusItem(withLength: NSStatusItem.squareLength)
         item.autosaveName = "Prompt"