feat: scaffold React+TS frontend with types and Tailwind tokens (Phases 1, 2, 10)

Phase 1 — Project Scaffold:
- Vite + React-TS project in frontend/ with Tailwind v3, PostCSS, Autoprefixer
- clsx and react-router-dom installed
- Vite proxy configured for /api and /ws to localhost:8000
- Tailwind directives in src/index.css
- Makefile targets: frontend-dev, frontend-build
- app.py updated to serve frontend/dist/ with SPA catch-all fallback

Phase 2 — Type Definitions:
- TypeScript types in frontend/src/types/game.ts (Phase, Card, Player,
  GameState, WsIncoming, NarrationLine)
- Constants in frontend/src/constants.ts (SEAT_COLOURS, PHASES)

Phase 10 — Tailwind Colour Tokens:
- Custom color tokens for bg, accent, life, seat, card color groups
- Additional tokens from index.html audit: border, phase, btn, text, highlight
- Custom pulse animation keyframe

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Makefile

@@ -16,7 +16,7 @@ UVICORN ?= uvicorn
 PORT    ?= 8000
 SRC     = src/commander_ai_lab
 
-.PHONY: test test-unit test-integration test-benchmark coverage serve lint fmt clean
+.PHONY: test test-unit test-integration test-benchmark coverage serve lint fmt clean frontend-dev frontend-build
 
 test:
 	$(PYTHON) -m pytest tests/ -q
@@ -63,3 +63,9 @@ clean:
 	find . -type d -name __pycache__ -exec rm -rf {} + 2>/dev/null || true
 	find . -type f -name '*.pyc' -delete
 	rm -rf .coverage htmlcov .mypy_cache .ruff_cache dist build
+
+frontend-dev:
+	cd frontend && npm run dev
+
+frontend-build:
+	cd frontend && npm run build