Add Railway deployment configuration

- Add Dockerfiles for backend (FastAPI) and frontend (nginx)
- Add railway.toml configs with health checks
- Add .dockerignore files for optimized builds
- Update config.py to auto-convert Railway DATABASE_URL format
- Add FRONTEND_URL env var for production CORS

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/.dockerignore

@@ -0,0 +1,20 @@
+__pycache__
+*.pyc
+*.pyo
+*.pyd
+.Python
+.env
+.env.*
+.venv
+venv/
+.git
+.gitignore
+.pytest_cache
+.mypy_cache
+*.egg-info
+dist/
+build/
+.coverage
+htmlcov/
+.tox
+*.log