Use the Maven Wrapper in the Gitea workflow and check the registry token

act-based Gitea runner images do not ship Maven, so the publish job failed
with 'mvn: command not found'. Add the Maven Wrapper (Maven 3.9.11) and use
./mvnw. Fail early with a clear message when REGISTRY_TOKEN is not available.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01G71TQ5jDETVwdUJxGAwaiT

.gitea/workflows/publish.yml

@@ -6,6 +6,7 @@
 #   manual run          -> whatever pom.xml says
 #
 # Needs the repository/organization secret REGISTRY_TOKEN: a Gitea access token with "write:package" scope.
+# Uses the Maven Wrapper (./mvnw): act-based runner images do not ship Maven.
 name: Publish
 
 on:
@@ -21,6 +22,15 @@ jobs:
   publish:
     runs-on: ubuntu-latest
     steps:
+      - name: Check registry token
+        env:
+          REGISTRY_TOKEN: ${{ secrets.REGISTRY_TOKEN }}
+        run: |
+          if [ -z "$REGISTRY_TOKEN" ]; then
+            echo "::error::Secret REGISTRY_TOKEN is not set or not available to this repository (Settings > Actions > Secrets)."
+            exit 1
+          fi
+
       - uses: actions/checkout@v4
 
       - uses: actions/setup-java@v4
@@ -35,12 +45,12 @@ jobs:
 
       - name: Set release version from tag
         if: startsWith(gitea.ref, 'refs/tags/v')
-        run: mvn -B -ntp versions:set -DnewVersion="${GITEA_REF_NAME#v}" -DgenerateBackupPoms=false
+        run: ./mvnw -B -ntp versions:set -DnewVersion="${GITEA_REF_NAME#v}" -DgenerateBackupPoms=false
         env:
           GITEA_REF_NAME: ${{ gitea.ref_name }}
 
       - name: Build, test and publish
-        run: mvn -B -ntp deploy -DaltDeploymentRepository="gitea::${REGISTRY_URL}"
+        run: ./mvnw -B -ntp deploy -DaltDeploymentRepository="gitea::${REGISTRY_URL}"
         env:
           REGISTRY_USERNAME: ${{ gitea.actor }}
           REGISTRY_TOKEN: ${{ secrets.REGISTRY_TOKEN }}