chore: update api schema and metadata

[hotdata-automation]

Auto-generated from the updated HotData OpenAPI spec.
Source: https://github.com/hotdata-dev/www.hotdata.dev/pull/235

[claude]

Auto-generated OpenAPI client update. Verified: Datasets API removal and Usage API addition are wired consistently across hotdata/__init__.py, hotdata/api/__init__.py, and hotdata/models/__init__.py; no dangling references to removed dataset symbols; no broken README doc links; tests and CHANGELOG updated. LGTM.

[zfarrell]

Closing as a redundant regen. #123 was generated from the same spec state as #122 (both branched off 37f628c ~40 min apart) and has zero SDK/spec delta over current main now that #122 is merged (git diff main..123 -- hotdata/ openapi.yaml is empty). Its only net content is the stale dataset integration tests that #122 removed, which would re-break integration with ModuleNotFoundError: hotdata.api.datasets_api. Nothing to merge here.