ci: skip publish when the version is already on npm

.github/workflows/npm-publish.yml

@@ -65,8 +65,30 @@ jobs:
       - name: Install dependencies
         run: npm ci
 
+      # Skip when this exact version is already on npm. `npm publish` over an
+      # existing version is a hard E403, which turned every unbumped merge —
+      # Dependabot's, and CI-only PRs now that the bump gate exempts them —
+      # into a red publish run (run 33714086138, 2026-09-02). The package is
+      # `access: restricted`, so the lookup needs the read-only NPM_TOKEN;
+      # the publish itself stays on OIDC trusted publishing.
+      - name: Check if version already published
+        id: check
+        shell: bash
+        env:
+          NODE_AUTH_TOKEN: ${{ secrets.NPM_TOKEN }}
+        run: |
+          set -euo pipefail
+          NAME=$(node -p "require('./package.json').name")
+          VERSION=$(node -p "require('./package.json').version")
+          if npm view "${NAME}@${VERSION}" version >/dev/null 2>&1; then
+            echo "published=true" >> "$GITHUB_OUTPUT"
+            echo "::notice::${NAME}@${VERSION} already on npm — no version bump on this commit, skipping publish."
+          else
+            echo "published=false" >> "$GITHUB_OUTPUT"
+            echo "${NAME}@${VERSION} not yet published — will publish."
+          fi
+
       # No build step: this package ships index.js / index.d.ts directly.
-      # `npm publish` is a no-op failure if the version already exists, so a
-      # push without a version bump simply doesn't release.
       - name: Publish to npm
+        if: steps.check.outputs.published != 'true'
         run: npm publish