fix(ci) missing package.json for shell-mcp-tool (#10135)

## Summary
This _should_ be the final place to fix.

.github/workflows/shell-tool-mcp.yml

@@ -445,6 +445,9 @@ jobs:
       id-token: write
       contents: read
     steps:
+      - name: Checkout repository
+        uses: actions/checkout@v6
+
       - name: Setup pnpm
         uses: pnpm/action-setup@v4
         with: