chore: initial project setup

Phase 0 — full project scaffold with:
- Backend: FastAPI + SQLAlchemy 2.0 async + Alembic + PostgreSQL 16
- Frontend: React 18 + TypeScript + Vite + Tailwind CSS + shadcn/ui
- Docker Compose (prod + dev override with hot-reload)
- Health endpoint, CORS config, API proxy, env template

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

backend/requirements.txt

@@ -0,0 +1,14 @@
+fastapi==0.115.6
+uvicorn[standard]==0.34.0
+sqlalchemy[asyncio]==2.0.36
+asyncpg==0.30.0
+alembic==1.14.1
+pydantic==2.10.4
+pydantic-settings==2.7.1
+python-jose[cryptography]==3.3.0
+passlib[bcrypt]==1.7.4
+python-multipart==0.0.20
+httpx==0.28.1
+weasyprint==63.1
+pytest==8.3.4
+pytest-asyncio==0.25.0