Deleted unused `.github` workflows and configurations, including obsolete CI/CD pipelines and PR templates, which were no longer executed after the migration to Gitea. Migrated the `PR Guard` workflow for hardcoded version checks to `.gitea/workflows/pr-guard.yaml`. Verified functional workflows in Gitea (e.g., Docker publish). Documented changes and rationale in session logs.
Signed-off-by: Stefan Mogeritsch <stefan.mo.co@gmail.com>
