CVE-2026-118504: Gitea issue changes on archived repositories through the API

The web interface blocks issue and pull request changes on archived repositories, but several issue routes of the REST API did not check whether the repository is archived. A user allowed to change issues of an archived repository could use the API to edit, close or delete issues, change labels and deadlines, add or delete tracked time and stopwatches, add reactions, change issue blocks, and pin issues, altering data that archiving is meant to freeze. Gitea 28.2.0 added the check to the issue edit, delete and label routes; Gitea 28.3.0 applies it to all modifying repository API requests.