Adds a manual release workflow input,
`skip-prior-published-package-checks`, for core releases.
The workflow dispatch dropdown supports:
- `none`
- `anthropic`
- `openai`
- `all`
When a partner is selected, that matrix entry records an explicit
skipped step and does not run the prior-published package test. The
default remains `none`, so existing release behavior is unchanged unless
the release operator opts into a skip.
AI-agent assistance was used to prepare this workflow update.