Use yarn npm publish with OIDC for trusted publishing

- Upgrade to Yarn 4.12.0 for OIDC support (PR yarnpkg/berry#6898)
- Replace npx npm@latest publish --provenance with yarn npm publish
- Provenance is automatic with OIDC trusted publishing
- Add packageManager field where missing

Author: hillna

.github/workflows/ci.yml

@@ -36,4 +36,4 @@ jobs:
       - run: yarn pack
       - name: Publish to NPM
         if: ${{ startsWith(github.ref, 'refs/tags/v') }}
-        run: npx npm@latest publish package.tgz --provenance --access public
+        run: yarn npm publish package.tgz --access public --provenance

package.json

@@ -52,5 +52,5 @@
     "typescript": "5.9.3",
     "typescript-eslint": "8.52.0"
   },
-  "packageManager": "yarn@4.9.2"
+  "packageManager": "yarn@4.12.0"
 }