Initial commit: backend scaffold, auth, frontend login

- FastAPI + SQLAlchemy async + Alembic + Postgres backend
- Auth: JWT access + rotating refresh tokens, argon2, roles, audit log
- React 19 + Vite frontend: login page, protected route, auth context
- Docker Compose: postgres, redis, migrate, api, worker (placeholder), frontend/nginx

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

.dockerignore

@@ -0,0 +1,12 @@
+**/node_modules
+**/dist
+**/.vite
+frontend/.env*
+backend/.venv
+backend/__pycache__
+backend/**/__pycache__
+backend/.pytest_cache
+backend/.ruff_cache
+.git
+.env
+*.md