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/Resources/ExerciseMotions/Meditation.info.md

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+# Meditation
+
+Sit tall with the legs crossed, rest the hands on the knees, and follow the
+breath. A timed stillness practice that lowers stress, settles the nervous
+system, and closes a session — or a day — with focus.
+
+- **Category:** Mindfulness
+- **Type:** Seated meditation (timed hold)
+- **Targets:** Breath, focus, posture
+- **Prescription:** Sit 5–10 min, attention on the breath, returning to it whenever the mind wanders
+- **Defaults:** 1 × 300 s
+
+## Setup
+
+Sit on the floor (or a cushion) with the legs crossed — lotus, half-lotus, or a
+simple cross, whatever the hips allow. Stack the spine tall, rest the hands on
+the knees, and soften the gaze or close the eyes.
+
+## Execution
+
+1. Lengthen up through the crown of the head, letting the shoulders drop.
+2. Breathe slowly through the nose — a long inhale, a longer exhale.
+3. Rest the attention on the breath moving in and out.
+4. When the mind wanders, notice it without judgment and return to the breath.
+
+## Cues
+
+- Sit on the front edge of a cushion to tilt the pelvis and free the spine.
+- Let the breath deepen on its own — observe it rather than forcing it.
+- Keep the face, jaw, and hands soft; effort lives only in the tall spine.
+
+## Common Mistakes
+
+- Slumping through the lower back as the sit goes on.
+- Chasing every thought instead of letting it pass.
+- Straining into a full lotus the hips aren't ready for — a simple cross works.
+
+## Progression
+
+A few minutes seated comfortably → longer sits with a steady tall spine →
+half-lotus or full lotus as hip mobility allows.