Fix dispatch failures and disable automatic cleanup

1. Quote RELEASE_TAG env vars in all workflow files. Unquoted
   ${{ inputs.tag }} caused YAML parse errors on some Gitea runners,
   making dispatch return HTTP 500 for Linux/macOS.

2. Disable automatic release cleanup in both coordinators. The cleanup
   races with async builds -- it deletes the release before builds
   finish uploading their assets. Clean up old releases manually
   from the Gitea UI instead.

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

.gitea/workflows/sidecar-release.yml

@@ -128,37 +128,5 @@ jobs:
             echo "  -> HTTP ${HTTP_CODE}"
           done
 
-      - name: Clean up old sidecar releases
-        if: steps.check_changes.outputs.has_changes == 'true'
-        env:
-          BUILD_TOKEN: ${{ secrets.BUILD_TOKEN }}
-        run: |
-          REPO_API="${GITHUB_SERVER_URL}/api/v1/repos/${GITHUB_REPOSITORY}"
-          KEEP=2
-
-          echo "Cleaning up old sidecar releases (keeping latest ${KEEP})..."
-
-          # Get all sidecar releases (sidecar-v* tags)
-          RELEASES=$(curl -s -H "Authorization: token ${BUILD_TOKEN}" \
-            "${REPO_API}/releases?limit=50" | jq -c '[.[] | select(.tag_name | startswith("sidecar-v"))]')
-
-          TOTAL=$(echo "$RELEASES" | jq 'length')
-          echo "Found ${TOTAL} sidecar releases"
-
-          if [ "$TOTAL" -le "$KEEP" ]; then
-            echo "Nothing to clean up"
-            exit 0
-          fi
-
-          # Skip the newest KEEP releases, delete the rest
-          echo "$RELEASES" | jq -c ".[$KEEP:][]" | while read -r release; do
-            ID=$(echo "$release" | jq -r '.id')
-            TAG=$(echo "$release" | jq -r '.tag_name')
-
-            echo "  Deleting sidecar release ${TAG} (ID: ${ID})..."
-            curl -s -X DELETE -H "Authorization: token ${BUILD_TOKEN}" \
-              "${REPO_API}/releases/${ID}"
-            # Keep the git tag -- only delete the release (assets).
-            # Deleting tags breaks builds that haven't checked out yet.
-          done
-          echo "Cleanup complete"
+      # NOTE: Automatic cleanup disabled -- it races with async builds.
+      # Clean up old releases manually from the Gitea UI when needed.