fix(ci): skip docker if unavailable, no latest tag for prereleases

Gitea: Skip docker build gracefully if docker command not available
GitHub: Only tag as latest for stable releases (not alpha/beta/rc)

.gitea/workflows/release.yml

@@ -48,8 +48,10 @@ jobs:
 
       - name: Build Docker image
         run: |
-          docker build -t ffmpeg-worker:${{ steps.version.outputs.VERSION }} .
-          docker tag ffmpeg-worker:${{ steps.version.outputs.VERSION }} ffmpeg-worker:latest
-
-      - name: List images
-        run: docker images | grep ffmpeg-worker
+          if command -v docker &> /dev/null; then
+            docker build -t ffmpeg-worker:${{ steps.version.outputs.VERSION }} .
+            docker tag ffmpeg-worker:${{ steps.version.outputs.VERSION }} ffmpeg-worker:latest
+            docker images | grep ffmpeg-worker
+          else
+            echo "Docker not available - skipping build"
+          fi