feat: multi-dimensional rest days + development routes architecture (v9d → v9e)
## Changes:
**Frontend:**
- Fix double icon in rest day list (removed icons from FOCUS_LABELS)
- Icon now shows once with proper styling
**Migration 011:**
- Remove UNIQUE constraint (profile_id, date) from rest_days
- Allow multiple rest day types per date
- Use case: Muscle recovery + Mental rest same day
**Architecture: Development Routes**
New document: `.claude/docs/functional/DEVELOPMENT_ROUTES.md`
6 Independent Development Routes:
- 💪 Kraft (Strength): Muscle, power, HIIT
- 🏃 Kondition (Conditioning): Cardio, endurance, VO2max
- 🧘 Mental: Stress, focus, competition readiness
- 🤸 Koordination (Coordination): Balance, agility, technique
- 🧘♂️ Mobilität (Mobility): Flexibility, ROM, fascia
- 🎯 Technik (Technique): Sport-specific skills
Each route has:
- Independent rest requirements
- Independent training plans
- Independent progress tracking
- Independent goals & habits
**Future (v9e):**
- Route-based weekly planning
- Multi-route conflict validation
- Auto-rest on poor recovery
- Route balance analysis (KI)
**Future (v9g):**
- Habits per route (route_habits table)
- Streak tracking per route
- Dashboard route-habits widget
**Backlog Updated:**
- v9d: Rest days ✅ (in testing)
- v9e: Development Routes & Weekly Planning (new)
- v9g: Habits per Route (extended)
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>