ci: use pnpm instead of npm (repo uses pnpm-lock.yaml)

Author: liz709

.github/workflows/ci.yml

@@ -14,9 +14,12 @@ jobs:
         node-version: [18, 20, 22]
     steps:
       - uses: actions/checkout@v4
+      - uses: pnpm/action-setup@v3
+        with:
+          version: 9
       - uses: actions/setup-node@v4
         with:
           node-version: ${{ matrix.node-version }}
-      - run: npm ci
-      - run: npm run typecheck
-      - run: npm test -- run
+      - run: pnpm install
+      - run: pnpm run typecheck
+      - run: pnpm test -- run