fix: set DOCS_VERSION only for tag builds to preserve dev fallback

Addresses review comment: on workflow_dispatch runs github.ref_name is the branch name not a tag

Author: 23prime

.github/workflows/docs.yml

@@ -32,7 +32,7 @@ jobs:
         run: pnpm build
         working-directory: website
         env:
-          DOCS_VERSION: ${{ github.ref_name }}
+          DOCS_VERSION: ${{ startsWith(github.ref, 'refs/tags/') && github.ref_name || '' }}
 
       - uses: actions/upload-pages-artifact@v4
         with: