Restructure into a three-tab app with Progress, goals, and Meditation

The UX redesign's first landing (spec in UX-REDESIGN.md): ContentView
becomes a Today / Progress / Settings TabView, "Routine" replaces
"Split" in every user-facing string and view name (code-level types
keep their names), and workout starting moves to shared
WorkoutStarter / StartedWorkoutNavigator plumbing.

- New Progress tab: weekly goal streaks, workout trends, per-exercise
  weight progression, achievements, and the full history list
  (WorkoutLogsView -> WorkoutHistoryView).
- Goals: stable categories workouts roll up to, managed from Settings.
- New Meditation exercise + starter routine; timed sits record to
  Apple Health as Mind & Body sessions.

Claude-Session: https://claude.ai/code/session_012qw2itfzKyEJ1HpsFt8Ex4

Workouts Watch App/Views/WorkoutLogListView.swift

@@ -35,16 +35,16 @@ struct WorkoutLogListView: View {
         _doc = State(initialValue: WorkoutDocument(fromLive: workout) ?? .deletedPlaceholder)
     }
 
-    /// The split this workout came from (read-only on the watch), used to offer
+    /// The routine this workout came from (read-only on the watch), used to offer
     /// additional exercises that aren't logged yet. Fetched imperatively — *not* via
-    /// `@Query` — so the list body never observes the live `Split` or traverses its
+    /// `@Query` — so the list body never observes the live `Routine` or traverses its
     /// `exercises` relationship during a render. Doing so (a `@Query`-observed model
     /// whose to-many relationship is read in `body`) drove a SwiftData re-render loop
     /// that hung the watch. `availableExercises` is therefore only ever evaluated from
     /// the picker sheet's closure, not from `body`.
-    private var split: Split? {
-        guard let splitID = doc.splitID else { return nil }
-        return CacheMapper.fetchSplit(id: splitID, in: modelContext)
+    private var routine: Routine? {
+        guard let routineID = doc.routineID else { return nil }
+        return CacheMapper.fetchRoutine(id: routineID, in: modelContext)
     }
 
     private var sortedLogs: [WorkoutLogDocument] {
@@ -52,9 +52,9 @@ struct WorkoutLogListView: View {
     }
 
     private var availableExercises: [Exercise] {
-        guard let split else { return [] }
+        guard let routine else { return [] }
         let existingNames = Set(doc.logs.map { $0.exerciseName })
-        return split.exercisesArray.filter { !existingNames.contains($0.name) }
+        return routine.exercisesArray.filter { !existingNames.contains($0.name) }
     }
 
     var body: some View {
@@ -74,10 +74,10 @@ struct WorkoutLogListView: View {
                 }
             }
 
-            // Gate on the *resolved* split, not the stale `splitID` string — a split
+            // Gate on the *resolved* routine, not the stale `routineID` string — a routine
             // deleted on the phone leaves the id dangling, and offering Add Exercise
             // against it would only show a misleading "All exercises added" picker.
-            if split != nil {
+            if routine != nil {
                 Section {
                     Button {
                         showingExercisePicker = true
@@ -96,13 +96,13 @@ struct WorkoutLogListView: View {
                 ContentUnavailableView(
                     "No Exercises",
                     systemImage: "figure.strengthtraining.traditional",
-                    description: Text(split == nil
+                    description: Text(routine == nil
                         ? "No exercises in this workout."
                         : "Tap + to add exercises.")
                 )
             }
         }
-        .navigationTitle(doc.splitName ?? Split.unnamed)
+        .navigationTitle(doc.routineName ?? Routine.unnamed)
         // Absorb phone edits while this screen is open (H1's watch-side gap):
         // without this, the snapshot stays frozen at init, and the next watch
         // tick — made against a state that's missing the phone's edit — would be
@@ -120,7 +120,7 @@ struct WorkoutLogListView: View {
             }
         }
         .navigationDestination(item: $selectedLogID) { logID in
-            // RunFlowView hosts the run and, in a flow-mode split, auto-advances across
+            // RunFlowView hosts the run and, in a flow-mode routine, auto-advances across
             // exercises. It owns the live-run mirror wiring (incoming-frame filter,
             // `navigatedRunID`, and the parameterized live-ended signal) since the on-screen
             // log advances during a flowing run.