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/RunFlowView.swift

@@ -8,10 +8,10 @@
 import SwiftUI
 
 /// Thin coordinator that lets a single pushed run walk across exercises in a flow-mode
-/// split (`autoAdvance`). It owns which log is on screen and swaps it when the running
+/// routine (`autoAdvance`). It owns which log is on screen and swaps it when the running
 /// `ExerciseProgressView` finishes an exercise; `.id(currentLogID)` rebuilds the child
 /// fresh for each exercise, so the delicate per-exercise run/mirror machinery stays
-/// exactly as it is. For a non-flow split it's transparent — one exercise, unchanged.
+/// exactly as it is. For a non-flow routine it's transparent — one exercise, unchanged.
 struct RunFlowView: View {
     @Environment(WatchConnectivityBridge.self) private var bridge