chore: migrate from npm to pnpm

cloudflare-worker/.github/workflows/ci.yml

@@ -10,12 +10,15 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
+      - uses: pnpm/action-setup@v4
+        with:
+          version: 11
       - uses: actions/setup-node@v4
         with:
           node-version: '22'
-          cache: 'npm'
-      - run: npm ci
-      - run: npm test
-      - run: npx wrangler deploy --dry-run
+          cache: 'pnpm'
+      - run: pnpm install --frozen-lockfile
+      - run: pnpm test
+      - run: pnpm exec wrangler deploy --dry-run
         env:
           CLOUDFLARE_API_TOKEN: dummy