Preview the next exercise and count into each set during rests

The run flow's between-exercise rest now previews the next exercise — its
figure and a large "Coming up" name — and the hands-free narration gains a
per-second count-in ("<Exercise>, in 1, 2, 3, GO!") spoken before every set,
plus a "Coming up" announcement as a between-exercise rest begins. A new
Settings > Narration picker chooses the count-in cues, the setup/form read,
or both.

Also fixes spoken cues going silent after the first exercise in a flow split:
the stop-on-teardown moved from the per-exercise view (rebuilt on every
hand-off) to the run host, which stays mounted for the whole run. The audio
session now holds its duck across the per-second count so background music
doesn't pulse between words.

Claude-Session: https://claude.ai/code/session_01BQcEWmAPA78338QuEwRkAh

Workouts/Views/Settings/SettingsView.swift

@@ -22,6 +22,7 @@ struct SettingsView: View {
     @AppStorage("weightUnit") private var weightUnit: WeightUnit = .lb
     @AppStorage("figureProfile") private var figureProfile: FigureProfile = .neutral
     @AppStorage("speakExerciseCues") private var speakExerciseCues = false
+    @AppStorage("spokenCueStyle") private var spokenCueStyle: SpokenCueStyle = .cues
     @AppStorage(SpeechSettings.voiceIdentifierKey) private var speechVoiceIdentifier = ""
 
     @State private var isRestoringSeeds = false
@@ -222,6 +223,14 @@ struct SettingsView: View {
 
             Toggle("Speak Exercise Cues", isOn: $speakExerciseCues)
 
+            if speakExerciseCues {
+                Picker("Narration", selection: $spokenCueStyle) {
+                    ForEach(SpokenCueStyle.allCases) { style in
+                        Text(style.displayName).tag(style)
+                    }
+                }
+            }
+
             Picker("Voice", selection: $speechVoiceIdentifier) {
                 Text("Automatic").tag("")
                 ForEach(installedVoices, id: \.identifier) { voice in
@@ -257,7 +266,7 @@ struct SettingsView: View {
         } header: {
             Text("Voice")
         } footer: {
-            Text("Speak Exercise Cues reads each exercise's setup and form cues aloud when you start it; tap a library exercise's speaker to hear its full instructions anytime.")
+            Text("Speak Exercise Cues narrates a running workout hands-free. Coming Up & Countdown announces the next exercise during a rest and counts “in 1, 2, 3, GO!” before each set; Setup & Form Read reads each exercise's cues aloud when it starts. Tap a library exercise's speaker to hear its full instructions anytime.")
         }
     }