* feat(codex-node): add dataset deletion API to Codex node
* feat(api): add deletion of local datasets to API
* fix: logging, remove garbage, drop some CORS headers from DELETE request
* fix: change empty response return code to 204 instead of 200
* fix: add time-based idling to avoid locking up the node during deletes, fix API status code
* fix: uncomment commented tests committed by accident
* fix: return correct code when missing CID is a Manifest CID; add back CORS headers
* fix: remove lingering echo