### What
Ensure `create_release` accepts and forwards a `body` so release notes are created as provided.
### Why
Previously, the `body` parameter wasn’t threaded through, resulting in empty release notes even when a body was supplied.
### How
- Add `body` parameter to the function signature
- Thread `body` through handler/service to the API call
- Light refactor for clarity; no breaking changes
### Testing
- Manual: created a release with a non-empty body and confirmed it appears in the UI and in the releases API response
### Links
Fixesgitea/gitea-mcp#81
Reviewed-on: https://gitea.com/gitea/gitea-mcp/pulls/82
Reviewed-by: hiifong <i@hiif.ong>
Co-authored-by: meestark <meestark@meestark.net>
Co-committed-by: meestark <meestark@meestark.net>
