Add quick feedback UI after exercises

[apermo]

Summary

Add a quick feedback prompt after completing each exercise, making it easy to tell the AI how it went.

UI Flow

1. User completes rep counter
2. Completion celebration appears
3. Quick feedback buttons shown below
4. User taps rating (or skips)
5. Feedback saved, optional note field expands

UI Design

┌─────────────────────────────┐
│      ✓ Geschafft!           │
│                             │
│   Wie war die Übung?        │
│                             │
│  [😰] [😓] [👍] [💪] [🚀]   │
│  hard  ok  good easy  too   │
│                             │
│  [Notiz hinzufügen...]      │
│                             │
│         [Weiter]            │
└─────────────────────────────┘

Rating Options

Icon	Value	Label
😰	too_hard	Zu schwer
😓	hard	Anstrengend
👍	good	Gut
💪	easy	Leicht
🚀	too_easy	Zu leicht

Implementation

• Integrate with exercise completion flow
• Call feedback API endpoint
• Optional: AI auto-suggests adjustment for extreme ratings
• Store actual weight/reps if different from planned

Dependencies

• Add exercise feedback API endpoints #136 (feedback API endpoint)

Part of

Phase 4: Smart Feedback Loop