Add a live status panel between the run screen's halves

Replaces the small target-HR pill on the iPhone run screen with a
glanceable big-digit strip between the timer flow and the figure —
heart rate (band-tinted with the cue arrow when the run carries a
target), HR zone, active calories, and the workout stopwatch. A
horizontal band in portrait, a vertical column in landscape (the
inverse of the half-and-half split, so it always sits between them).

The watch now rides the running calorie total and the HR zone (1-5,
computed watch-side where max HR is known) along with each live HR
sample; absent keys keep older builds wire-compatible both ways.
LiveRunState holds all three under the shared staleness expiry. The
screenshot rig seeds believable values so the run capture shows the
panel populated.

Workouts Watch App/Connectivity/WatchConnectivityBridge.swift

@@ -221,22 +221,28 @@ final class WatchConnectivityBridge: NSObject {
 
     /// Rounded bpm last sent and when, to throttle the forward: HR samples land every few
     /// seconds, but an unchanged reading only needs an occasional keep-alive so the phone's
-    /// staleness window doesn't blank the readout mid-run.
+    /// staleness window doesn't blank the readout mid-run. A zone flip breaks the throttle
+    /// so the panel's zone can't lag a boundary crossing by the keep-alive interval.
     private var lastHRSentBpm: Int?
+    private var lastHRSentZone: Int?
     private var lastHRSentAt = Date.distantPast
 
-    /// Forward a live heart-rate sample to a mirroring phone. Unlike the run frames this is
-    /// pure best-effort — reachable-only, no staging, no retry: a gauge, not a record. The
-    /// durable HR summary still lands in `WorkoutMetrics` when the session finishes.
-    func sendLiveHeartRate(_ bpm: Double) {
+    /// Forward a live sample (heart rate + running calories + zone) to a mirroring phone.
+    /// Unlike the run frames this is pure best-effort — reachable-only, no staging, no
+    /// retry: a gauge, not a record. The durable summary still lands in `WorkoutMetrics`
+    /// when the session finishes.
+    func sendLiveSample(_ sample: WorkoutSessionManager.LiveSample) {
         guard let session, session.activationState == .activated, session.isReachable else { return }
-        let rounded = Int(bpm.rounded())
+        let rounded = Int(sample.bpm.rounded())
         let now = Date()
-        if rounded == lastHRSentBpm, now.timeIntervalSince(lastHRSentAt) < 10 { return }
+        if rounded == lastHRSentBpm, sample.zone == lastHRSentZone,
+           now.timeIntervalSince(lastHRSentAt) < 10 { return }
         lastHRSentBpm = rounded
+        lastHRSentZone = sample.zone
         lastHRSentAt = now
-        session.sendMessage(WCPayload.encodeLiveHeartRate(bpm: bpm, at: now),
-                            replyHandler: nil, errorHandler: nil)
+        session.sendMessage(
+            WCPayload.encodeLiveHeartRate(bpm: sample.bpm, at: now, kcal: sample.kcal, zone: sample.zone),
+            replyHandler: nil, errorHandler: nil)
     }
 
     /// Apply a live-run frame the phone sent. Catches our send counter up first (shared per-run