chore(infra): add Railway, Docker, and CI/CD configuration

- Add railway.toml for Railway deployment
- Add Dockerfile for containerized builds
- Add GitHub Actions deploy workflow

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

railway.toml

@@ -0,0 +1,12 @@
+[build]
+builder = "dockerfile"
+
+[deploy]
+numReplicas = 1
+startCommand = "node dist/server.js"
+healthcheckPath = "/health"
+healthcheckTimeout = 30
+
+[variables]
+NODE_ENV = "production"
+PORT = "8080"