fix: rename GITEA_TOKEN to CI_TOKEN in workflows

- Change secret name from GITEA_TOKEN to CI_TOKEN
- Gitea doesn't allow secrets starting with GITEA_
- Update all checkout steps to use CI_TOKEN instead

.gitea/workflows/security-scan.yml

@@ -24,10 +24,10 @@ jobs:
             REF_NAME="main"
           fi
           
-          # Use Gitea token if available, otherwise try public access
-          if [ -n "${{ secrets.GITEA_TOKEN }}" ]; then
+          # Use CI token if available, otherwise try public access
+          if [ -n "${{ secrets.CI_TOKEN }}" ]; then
             git clone --depth 1 --branch "$REF_NAME" \
-              "https://${{ secrets.GITEA_TOKEN }}@git.michaelschiemer.de/${REPO}.git" \
+              "https://${{ secrets.CI_TOKEN }}@git.michaelschiemer.de/${REPO}.git" \
               /workspace/repo
           else
             # Try public HTTPS (works if repository is public)