ci: fix yarn cache path in release server job

setup-node cache:yarn needs cache-dependency-path since the frontend
lockfile lives at frontend/yarn.lock, not the repo root.

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.github/workflows/release.yml

@@ -22,6 +22,7 @@ jobs:
         with:
           node-version: 22
           cache: yarn
+          cache-dependency-path: frontend/yarn.lock
       - uses: actions/setup-go@v5
         with:
           go-version-file: go.mod