ci: add pre-verification with registry login test

.gitea/workflows/ci.yaml

@@ -54,6 +54,43 @@ jobs:
           SHORT_SHA=$(git rev-parse --short HEAD)
           echo "short_sha=${SHORT_SHA}" >> $GITHUB_OUTPUT
 
+      - name: Pre-verify Docker, Registry, and Credentials
+        run: |
+          echo "=== Docker Daemon Check ==="
+          if ! docker version &>/dev/null; then
+            echo "❌ FAILED: Docker daemon not accessible"
+            exit 1
+          fi
+          echo "✓ Docker daemon is running"
+          docker version --format "Engine: {{.Server.Version}}"
+          echo ""
+          echo "=== Registry Credentials Check ==="
+          if [ -z "${REGISTRY_USER}" ] || [ -z "${REGISTRY_TOKEN}" ]; then
+            echo "❌ FAILED: FORGEJO_REGISTRY_USER or FORGEJO_REGISTRY_TOKEN not set"
+            exit 1
+          fi
+          echo "✓ Registry credentials are set"
+          echo ""
+          echo "=== Registry Login Test ==="
+          if ! echo "${REGISTRY_TOKEN}" | docker login "${REGISTRY}" --username "${REGISTRY_USER}" --password-stdin &>/dev/null; then
+            echo "❌ FAILED: Registry login failed - credentials may be invalid"
+            exit 1
+          fi
+          echo "✓ Registry login successful"
+          docker logout "${REGISTRY}" &>/dev/null || true
+          echo ""
+          echo "=== Dockerfile Check ==="
+          if [ ! -f Dockerfile ]; then
+            echo "❌ FAILED: Dockerfile not found"
+            exit 1
+          fi
+          echo "✓ Dockerfile exists"
+          echo ""
+          echo "=== All pre-checks passed ==="
+        env:
+          REGISTRY_USER: ${{ secrets.FORGEJO_REGISTRY_USER }}
+          REGISTRY_TOKEN: ${{ secrets.FORGEJO_REGISTRY_TOKEN }}
+
       - name: Registry login
         run: |
           echo "${REGISTRY_TOKEN}" | docker login "${REGISTRY}" \