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>

frontend/.dockerignore

@@ -0,0 +1,10 @@
+node_modules
+dist
+.git
+.gitignore
+*.log
+.env
+.env.*
+.vscode
+coverage
+.eslintcache