Run build-image job on host to access Docker CLI

The node:22 container doesn't have Docker installed. Running
on the host label executes directly on the VPS where Docker
is available.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.gitea/workflows/ci.yml

@@ -26,7 +26,7 @@ jobs:
   build-image:
     if: startsWith(github.ref, 'refs/tags/')
     needs: check
-    runs-on: ubuntu-latest
+    runs-on: host
     steps:
       - uses: actions/checkout@v4