Update Dockerfile to enhance runtime configuration and health check

- Added `gosu` for safe privilege dropping in the entrypoint script.
- Updated the entrypoint to use `docker-entrypoint.sh` for improved container management.
- Ensured necessary directories are created with appropriate permissions during the build process.
- Enhanced health check command to verify service availability more reliably.

.gitattributes

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+*.sh text eol=lf