feat(watchos): mode Test (FC simulée) — valide le flux sans HealthKit

Bouton "Test (FC simulée)" qui envoie des samples synthétiques (FC ~110-150,
calories, distance, durée) via WCSession toutes les 2s, sans démarrer de séance
HealthKit. Permet de valider watch -> iPhone -> /live indépendamment de
l'autorisation Santé (bloquée par un sous-système Santé coincé sur la Watch).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

ios/App/CoachWatch/ContentView.swift

@@ -45,10 +45,18 @@ struct ActivityPickerView: View {
                             .frame(maxWidth: .infinity, alignment: .leading)
                     }
                 }
+                Button {
+                    workout.startSimulation()
+                } label: {
+                    Label("Test (FC simulée)", systemImage: "waveform.path.ecg")
+                        .frame(maxWidth: .infinity, alignment: .leading)
+                }
+                .tint(.gray)
+
                 if let message = workout.statusMessage {
                     Text(message)
                         .font(.footnote)
-                        .foregroundStyle(.red)
+                        .foregroundStyle(.secondary)
                 }
             }
             .padding(.horizontal, 4)

ios/App/CoachWatch/WorkoutManager.swift

@@ -24,6 +24,7 @@ final class WorkoutManager: NSObject, ObservableObject {
 
     private var lastSentAt = Date.distantPast
     private let sendInterval: TimeInterval = 2
+    private var simTask: Task<Void, Never>?
 
     private override init() { super.init() }
 
@@ -86,7 +87,47 @@ final class WorkoutManager: NSObject, ObservableObject {
 
     func pause() { session?.pause() }
     func resume() { session?.resume() }
-    func end() { session?.end() }
+
+    func end() {
+        if let simTask {
+            simTask.cancel()
+            self.simTask = nil
+            isRunning = false
+            statusMessage = nil
+        } else {
+            session?.end()
+        }
+    }
+
+    /// Mode test : FC simulée, sans HealthKit, pour valider le flux watch -> iPhone -> /live.
+    func startSimulation() {
+        guard !isRunning else { return }
+        isRunning = true
+        statusMessage = "Mode test — FC simulée"
+        let startedAt = Date()
+        simTask = Task { [weak self] in
+            while !Task.isCancelled {
+                guard let self else { return }
+                let elapsed = Date().timeIntervalSince(startedAt)
+                let hr = 110 + 40 * abs(sin(elapsed / 30))
+                let kcal = elapsed / 6
+                let dist = elapsed * 2.6
+                self.heartRate = hr
+                self.activeEnergyKcal = kcal
+                self.distanceMeters = dist
+                self.elapsedSec = elapsed
+                ConnectivityManager.shared.sendSample([
+                    "heartRate": hr,
+                    "activeEnergyKcal": kcal,
+                    "distanceMeters": dist,
+                    "elapsedSec": elapsed,
+                    "ts": Date().timeIntervalSince1970,
+                    "sim": true
+                ])
+                try? await Task.sleep(nanoseconds: 2_000_000_000)
+            }
+        }
+    }
 
     /// Appelé sur le main depuis le callback de collecte (hors-main).
     private func ingest(hr: Double?, kcal: Double?, dist: Double?, elapsed: TimeInterval) {