feat: add dev config and graceful config handling

- Add deploy/dev/config.yaml for dev environment testing
- Mount config from ./config.yaml instead of project root
- Create template config if missing and exit gracefully
- Update .gitignore to only ignore root config.yaml

deploy/dev/docker-compose.yml

@@ -8,7 +8,7 @@ services:
       - "${PORT:-3000}:3000"
     volumes:
       - ../../src:/app/src:ro
-      - ../../config.yaml:/app/config.yaml:ro
+      - ./config.yaml:/app/config.yaml:ro
     environment:
       - CONFIG_PATH=/app/config.yaml
     healthcheck: