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/ActiveWorkoutGateView.swift

@@ -11,7 +11,7 @@ import SwiftData
 /// Root of the watch app. The watch only runs the workouts that are currently
 /// active on the phone — there's no history browsing here. An "active" workout is a
 /// cached one that isn't finished (`notStarted` or `inProgress`); a workout is
-/// created on the phone as `notStarted` the moment a split is picked, and flips to
+/// created on the phone as `notStarted` the moment a routine is picked, and flips to
 /// `completed` once every exercise is done, at which point it drops off this list.
 ///
 /// The root shows every active workout (most-recent first); picking one opens its
@@ -20,7 +20,7 @@ struct ActiveWorkoutGateView: View {
     @Environment(WatchConnectivityBridge.self) private var bridge
 
     @Query(sort: \Workout.start, order: .reverse) private var workouts: [Workout]
-    @Query private var splits: [Split]
+    @Query private var routines: [Routine]
 
     /// Navigated workouts (depth 1). Held here — rather than relying on implicit
     /// `NavigationLink` destinations — so we can pop back to the gate the moment the phone
@@ -31,17 +31,17 @@ struct ActiveWorkoutGateView: View {
         workouts.filter { $0.status == .inProgress || $0.status == .notStarted }
     }
 
-    private func split(for workout: Workout) -> Split? {
-        guard let id = workout.splitID else { return nil }
-        return splits.first { $0.id == id }
+    private func routine(for workout: Workout) -> Routine? {
+        guard let id = workout.routineID else { return nil }
+        return routines.first { $0.id == id }
     }
 
-    /// True while the phone has this workout's exercise — or the split it came from — open
+    /// True while the phone has this workout's exercise — or the routine it came from — open
     /// in an editor. The watch parks such a run and blocks re-entry so the phone owns the
     /// edit and the watch can't forward a stale optimistic write over it.
     private func isLockedForEditing(_ workout: Workout) -> Bool {
         if let id = bridge.editingWorkoutID, id == workout.id { return true }
-        if let splitID = bridge.editingSplitID, splitID == workout.splitID { return true }
+        if let routineID = bridge.editingRoutineID, routineID == workout.routineID { return true }
         return false
     }
 
@@ -89,17 +89,17 @@ struct ActiveWorkoutGateView: View {
         // pop back to the gate so re-entry rebuilds a fresh working copy. Also pop if the run
         // we're inside was pruned (discarded/deleted on the phone, or aged out of the push).
         .onChange(of: bridge.editingWorkoutID) { _, _ in popIfNavigatedRunUnavailable() }
-        .onChange(of: bridge.editingSplitID) { _, _ in popIfNavigatedRunUnavailable() }
+        .onChange(of: bridge.editingRoutineID) { _, _ in popIfNavigatedRunUnavailable() }
         .onChange(of: workouts.map(\.id)) { _, _ in popIfNavigatedRunUnavailable() }
     }
 
     @ViewBuilder
     private func row(for workout: Workout) -> some View {
         if isLockedForEditing(workout) {
-            ActiveWorkoutRow(workout: workout, split: split(for: workout), editingOnPhone: true)
+            ActiveWorkoutRow(workout: workout, routine: routine(for: workout), editingOnPhone: true)
         } else {
             NavigationLink(value: ActiveWorkoutRoute(workoutID: workout.id)) {
-                ActiveWorkoutRow(workout: workout, split: split(for: workout))
+                ActiveWorkoutRow(workout: workout, routine: routine(for: workout))
             }
         }
     }
@@ -135,7 +135,7 @@ struct ActiveWorkoutGateView: View {
 
 private struct ActiveWorkoutRow: View {
     let workout: Workout
-    let split: Split?
+    let routine: Routine?
     /// When true, the phone is editing this run — render it dimmed and non-tappable.
     var editingOnPhone: Bool = false
 
@@ -144,13 +144,13 @@ private struct ActiveWorkoutRow: View {
 
     var body: some View {
         HStack(spacing: 10) {
-            Image(systemName: editingOnPhone ? "pencil" : (split?.systemImage ?? "figure.strengthtraining.traditional"))
+            Image(systemName: editingOnPhone ? "pencil" : (routine?.systemImage ?? "figure.strengthtraining.traditional"))
                 .font(.title3)
-                .foregroundStyle(split.map { Color.color(from: $0.color) } ?? .workTint)
+                .foregroundStyle(routine.map { Color.color(from: $0.color) } ?? .workTint)
                 .frame(width: 26)
 
             VStack(alignment: .leading, spacing: 2) {
-                Text(workout.splitName ?? Split.unnamed)
+                Text(workout.routineName ?? Routine.unnamed)
                     .font(.headline)
                     .lineLimit(1)