Fix two incorrect API URL paths in GiteaRepoManager by removing duplicate '/api/v1' prefix from admin users endpoints, and replace repository management call in main.py with a new delete_users_above_id method invocation using threshold ID 18 with purge and dry_run flags enabled.
The diff shows a single-line change in `gitea_api.py` where the URL path for repository deletion was corrected from `{self.api_url}/api/v1/repos/{owner}/{repo_name}` to `{self.api_url}/repos/{owner}/{repo_name}`. This fixes a broken endpoint because `self.api_url` already includes the `/api/v1` base path, causing a double prefix that would result in 404 errors in production.
retoor