fix(ci): use ubuntu-latest runner label to match Gitea runner

The runner is registered as ubuntu-latest, not linux-arm64.
The underlying hardware is ARM64 but the label must match.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.gitea/workflows/publish.yml

@@ -7,7 +7,7 @@ on:
 
 jobs:
   publish:
-    runs-on: linux-arm64
+    runs-on: ubuntu-latest
     container:
       image: node:22-bookworm-slim
     steps: