feat(macos): add native menu bar app with notch overlay

Introduces a SwiftUI companion app for the Fail Well PWA: menu bar
status item, popover with task list / record / history views, command
palette, and a Dynamic Island-style notch overlay that shows the active
step and timer beside the hardware notch and expands on hover to reveal
pause/next controls.

macos/Sources/FailWell/FailWellApp.swift

@@ -0,0 +1,114 @@
+import AppKit
+import KeyboardShortcuts
+import SwiftUI
+
+extension KeyboardShortcuts.Name {
+    static let togglePopover = Self("togglePopover", default: .init(.f, modifiers: [.control, .option, .command]))
+}
+
+@main
+struct FailWellApp: App {
+    @NSApplicationDelegateAdaptor(AppDelegate.self) private var appDelegate
+
+    var body: some Scene {
+        Settings {
+            SettingsView()
+                .environment(appDelegate.store)
+                .environment(appDelegate.router)
+                .environment(appDelegate.clock)
+        }
+    }
+}
+
+@MainActor
+final class AppDelegate: NSObject, NSApplicationDelegate {
+    let store = AppStore()
+    let router = Router()
+    let clock = Clock()
+
+    private var statusItem: NSStatusItem!
+    private var popover: NSPopover!
+    private var labelUpdater: Task<Void, Never>?
+    private var notchOverlay: NotchOverlayController?
+
+    func applicationDidFinishLaunching(_ notification: Notification) {
+        setupStatusItem()
+        setupPopover()
+        setupHotkey()
+        startLabelUpdates()
+        notchOverlay = NotchOverlayController(store: store, clock: clock)
+    }
+
+    func applicationWillTerminate(_ notification: Notification) {
+        labelUpdater?.cancel()
+        store.flush()
+    }
+
+    private func setupStatusItem() {
+        statusItem = NSStatusBar.system.statusItem(withLength: NSStatusItem.variableLength)
+        statusItem.behavior = .terminationOnRemoval
+        if let button = statusItem.button {
+            button.image = NSImage(systemSymbolName: "checklist", accessibilityDescription: "Fail Well")
+            button.imagePosition = .imageLeading
+            button.font = NSFont.monospacedDigitSystemFont(ofSize: 12, weight: .regular)
+            button.action = #selector(togglePopover(_:))
+            button.target = self
+        }
+    }
+
+    private func setupPopover() {
+        popover = NSPopover()
+        popover.behavior = .transient
+        popover.contentSize = NSSize(width: Theme.popoverWidth, height: Theme.popoverHeight)
+        popover.animates = false
+        let root = MenuBarPopover()
+            .environment(store)
+            .environment(router)
+            .environment(clock)
+        popover.contentViewController = NSHostingController(rootView: root)
+    }
+
+    private func setupHotkey() {
+        KeyboardShortcuts.onKeyDown(for: .togglePopover) { [weak self] in
+            self?.togglePopover(nil)
+        }
+    }
+
+    @objc func togglePopover(_ sender: Any?) {
+        if popover.isShown {
+            popover.performClose(sender)
+            return
+        }
+        guard let button = statusItem.button else { return }
+        NSApp.activate(ignoringOtherApps: true)
+        popover.show(relativeTo: button.bounds, of: button, preferredEdge: .minY)
+        popover.contentViewController?.view.window?.makeKey()
+    }
+
+    private func startLabelUpdates() {
+        labelUpdater = Task { [weak self] in
+            while !Task.isCancelled {
+                self?.refreshLabel()
+                try? await Task.sleep(for: .milliseconds(500))
+            }
+        }
+    }
+
+    private func refreshLabel() {
+        guard let button = statusItem.button else { return }
+        if let active = store.activeRecord,
+           let stepId = active.record.currentStepId,
+           let step = active.task.step(id: stepId),
+           let range = active.record.stepRecords[stepId]
+        {
+            let elapsed = clock.now.timeIntervalSince(range.start)
+            let icon = active.record.isPaused ? "pause.circle.fill" : "record.circle"
+            button.image = NSImage(systemSymbolName: icon, accessibilityDescription: nil)
+            let title = "\(TimeFormat.clock(elapsed)) \(step.title)"
+            button.title = title.count > 32 ? "\(title.prefix(30))…" : title
+        } else {
+            button.image = NSImage(systemSymbolName: "checklist", accessibilityDescription: nil)
+            button.title = ""
+        }
+    }
+}