- Move Corefile rendering logic into CoreDNSCorefileRenderer
- Add atomic rendering via envsubst with validation and preview
- Enforce strict error handling for missing files, invalid paths and permissions
- Integrate renderer into development compose workflow
- Rename DNS make targets for consistency (dns-setup / dns-remove)
- Rename test-act target to test-act-all
https://chatgpt.com/share/6970e503-e818-800f-8724-d791a3abfb33
