Mirror a live Apple Watch run on a propped-up iPhone

Add an ephemeral live-run presence channel (separate from the durable
iCloud progress sync) so a propped-up iPhone can mirror the Watch's
Ready → work/rest → Finish flow in real time as the user swipes.

Watch drives, phone mirrors (read-only), so there's no echo loop:
- Watch's ExerciseProgressView broadcasts a LiveProgress frame on every
  phase transition (and an ended signal on leave) via sendMessage,
  reachable-only — throwaway presence, never written to iCloud.
- Timers ride as wall-clock anchors (Date kept native in the WC dict to
  preserve sub-second precision), so both devices count independently
  off shared start times and stay in lockstep without streaming ticks.
- Phone holds a transient LiveRunState; ContentView auto-presents a
  read-only LiveProgressMirrorView full-screen cover while a run is live.

Claude-Session: https://claude.ai/code/session_01SCv7zvGFcKy47KSTnTLxRe

Workouts/AppServices.swift

@@ -13,13 +13,18 @@ final class AppServices {
     let watchBridge: PhoneConnectivityBridge
     let workoutLauncher = WorkoutLauncher()
 
+    /// Ephemeral live-run state fed by the watch, observed by the mirror UI. Not persisted.
+    let liveRunState: LiveRunState
+
     private var bootstrapTask: Task<Void, Never>?
 
     init() {
         let container = WorkoutsModelContainer.make()
         self.container = container
         self.syncEngine = SyncEngine(container: container)
-        self.watchBridge = PhoneConnectivityBridge(container: container, syncEngine: syncEngine)
+        let liveRunState = LiveRunState()
+        self.liveRunState = liveRunState
+        self.watchBridge = PhoneConnectivityBridge(container: container, syncEngine: syncEngine, liveRunState: liveRunState)
         #if DEBUG
         if ScreenshotSeed.isActive { ScreenshotSeed.populate(container.mainContext) }
         #endif