Start with the simplest vertical slice and build incrementally:

Phase 1: Foundation (Week 1-2)

1. Basic game state API - Create/get game state endpoint
2. Game state display - Show game state in frontend
3. Shared types working - Verify TypeScript types flow between services

Phase 2: Core Game (Week 3-4)

1. Player actions - Play card, discard card endpoints
2. Game rules validation - Prevent invalid moves
3. Game state updates - Real-time state changes in frontend
4. Basic UI - Playable cards, player hands, game board

Phase 3: Game Logic (Week 5-6)

1. Turn management - Player turns, game flow
2. Scoring system - Calculate points, detect game end
3. Game completion - Winner detection, restart game

Phase 4: AI Integration (Week 7-8)

1. Mock AI player - Random move selection first
2. RL training pipeline - Simple Q-learning or policy gradient
3. Model serving - Load trained model in backend
4. AI vs human gameplay - Integration testing

Phase 5: Polish (Week 9-10)