feat: redesign player with Dynamic Island, compact timer, and fix Live Activity timer drift

## What changed

### Player Redesign (video-first layout)
- New compact timer ring (110pt) with phase label, replaces 240pt ring
- Auto-hide top bar with block progress dots (3s auto-dismiss)
- Expandable now-playing music pill with skip control
- Bottom control bar with heart rate, play/pause, and skip
- Exercise caption with 'Next' preview during rest phases
- Compact round counter (capsule dots)

### Dynamic Island & Live Activities
- WorkoutLiveActivity widget: expanded, compact, and minimal views
- Phase-colored timers with Text(timerInterval:) countdown
- Shows exercise name, round progress, heart rate, music track
- MusicLiveActivity: standalone music now-playing widget
- LiveActivityMusicBars animated component
- Deep link from Dynamic Island back to app

### Timer Drift Fix (critical)
- Store a stable phaseEndDate once per phase instead of
  recalculating Date() + timeRemaining on every update
- Prevents dynamic island countdown from rubber-banding
  due to 5-second periodic update recalculation drift
- Reset phaseEndDate on phase change and resume from pause
- Guard Live Activity updates behind vm.isRunning to prevent
  premature creation when music track loads before workout start
- Fixes timer showing 0 in Dynamic Island when expanding
  from home screen

### New PlayerViewModel timer engine
- Full phase support: prep, warmup, work, rest,
  interBlockRest, cooldown, complete
- 1-second countdown with audio cues at 3-2-1
- Phase transitions with spring animation and haptics
- HealthKit live session integration
- Workout session recording with completion

### Music Service
- New MusicPlayerViewModel with vibe-based playlist loading
- Track info exposed for Dynamic Island display
- Skip track support from Dynamic Island notification action
- Automatic play/pause based on phase and running state

### Additional
- ZoneHighlightIcon component for HomeTab zone cards
- Updated watchOS localizations with complication strings
- Info.plist updated for widget extension

tabatago-swift/TabataGo/Models/MusicActivityAttributes.swift

@@ -0,0 +1,9 @@
+import ActivityKit
+
+struct MusicActivityAttributes: ActivityAttributes {
+    public struct ContentState: Codable, Hashable {
+        var title: String
+        var artist: String
+        var isPlaying: Bool
+    }
+}

tabatago-swift/TabataGo/Models/WorkoutActivityAttributes.swift

@@ -0,0 +1,16 @@
+import ActivityKit
+import Foundation
+
+struct WorkoutActivityAttributes: ActivityAttributes {
+    public struct ContentState: Codable, Hashable {
+        var exerciseName: String
+        var phase: String
+        var phaseEndDate: Date
+        var roundCurrent: Int
+        var roundTotal: Int
+        var heartRate: Double
+        var trackTitle: String
+        var trackArtist: String
+        var isPlaying: Bool
+    }
+}