ci: Workflow für node:20-bookworm-Runner, Runner-Stack im Swarm-Muster des bestehenden gitrunner

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.gitea/workflows/ci.yml

@@ -3,22 +3,19 @@ on:
   push:
   pull_request:
 
+# Läuft auf dem Runner-Label ubuntu-latest → node:20-bookworm (wie der bestehende Org-Runner).
+# Python kommt aus Debian bookworm (3.11), damit kein setup-python nötig ist.
 jobs:
   test:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
-      - uses: actions/setup-python@v5
-        with:
-          python-version: "3.12"
+      - name: Python installieren
+        run: |
+          apt-get update -qq
+          apt-get install -y -qq --no-install-recommends python3 python3-venv make >/dev/null
+          python3 --version
       - run: make dev
       - run: make lint
       - run: make test
       - run: make validate
-
-  compose:
-    runs-on: ubuntu-latest
-    continue-on-error: true   # braucht Docker Compose v2.24+ auf dem Runner
-    steps:
-      - uses: actions/checkout@v4
-      - run: make compose-check