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/Models/TaskRecord.swift

@@ -0,0 +1,41 @@
+import Foundation
+
+struct TaskRecord: Codable, Hashable, Sendable {
+    let taskId: String
+    var start: Date
+    var end: Date?
+    var stepRecords: [String: TimeRange]
+    var notes: String
+    var breakTime: TimeRange?
+    var currentStepId: String?
+
+    init(
+        taskId: String,
+        start: Date = Date(),
+        end: Date? = nil,
+        stepRecords: [String: TimeRange] = [:],
+        notes: String = "",
+        breakTime: TimeRange? = nil,
+        currentStepId: String? = nil
+    ) {
+        self.taskId = taskId
+        self.start = start
+        self.end = end
+        self.stepRecords = stepRecords
+        self.notes = notes
+        self.breakTime = breakTime
+        self.currentStepId = currentStepId
+    }
+
+    var isActive: Bool {
+        end == nil && currentStepId != nil
+    }
+
+    var isPaused: Bool {
+        breakTime != nil && breakTime?.end == nil
+    }
+
+    var hasStarted: Bool {
+        !stepRecords.isEmpty
+    }
+}