fix(ci): Scope napi-postinstall to release branch only

Only the release path uses --omit=optional which skips native bindings.
The regular npm ci path installs them via the lockfile.

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

Author: romtsn

.github/workflows/test_node.yml

@@ -96,9 +96,10 @@ jobs:
         if: ${{ inputs.triggered-by-release }}
         run: npm install --omit=optional --ignore-scripts
 
-      # --ignore-scripts skips napi-postinstall which installs native resolver
-      # bindings required by Jest 30's @unrs/resolver
-      - name: Install native bindings
+      # --omit=optional skips native resolver bindings required by Jest 30.
+      # napi-postinstall installs the correct platform-specific binary.
+      - name: Install native bindings (for pushes to release branch)
+        if: ${{ inputs.triggered-by-release }}
         run: npx napi-postinstall unrs-resolver
 
       - name: Download build artifact