Block publishing until all 5 native addon prebuilds are verified

The verify-prebuilds job was just printing ls output and had no teeth.
It now checks that all expected .node files are present and fails if
any are missing. Publish is gated behind this check, so a broken or
incomplete matrix build can never reach npm.

Author: oetr

.github/workflows/release.yaml

@@ -57,13 +57,22 @@ jobs:
           pattern: native-addon-*
           path: prebuilds
           merge-multiple: true
-      - name: list prebuilds
-        run: ls -lh prebuilds/
+      - name: verify all platforms are present
+        run: |
+          expected="fuzzer-darwin-arm64.node fuzzer-darwin-x64.node fuzzer-linux-arm64.node fuzzer-linux-x64.node fuzzer-win32-x64.node"
+          for f in $expected; do
+            if [ ! -f "prebuilds/$f" ]; then
+              echo "MISSING: $f"
+              exit 1
+            fi
+          done
+          echo "All 5 prebuilds present:"
+          ls -lh prebuilds/
 
   publish:
     name: publish
     if: startsWith(github.ref, 'refs/tags/')
-    needs: [prebuilds]
+    needs: [verify-prebuilds]
     runs-on: ubuntu-latest
     permissions:
       contents: write # for creating releases