Fix GitHub Action pnpm version mismatch

- Change pnpm version from 'latest' to '10.13.1' to match package.json
- Resolves ERR_PNPM_BAD_PM_VERSION error in GitHub Actions
- Ensures consistent pnpm version across local and CI environments

🤖 Generated with [Claude Code](https://claude.ai/code)

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

Author: naivefun

.github/workflows/deploy-docs.yml

@@ -26,7 +26,7 @@ jobs:
     - name: Setup pnpm
       uses: pnpm/action-setup@v4
       with:
-        version: latest
+        version: 10.13.1
 
     - name: Setup Node.js
       uses: actions/setup-node@v4