chore: migrate from npm to pnpm

Replace package-lock.json with pnpm-lock.yaml, add packageManager field,
and update GitHub Actions workflow to use pnpm/action-setup@v4 with
frozen-lockfile installs.

2016/.github/workflows/deploy.yml

@@ -20,22 +20,26 @@ jobs:
     steps:
       - uses: actions/checkout@v4
 
+      - uses: pnpm/action-setup@v4
+        with:
+          version: 11
+
       - uses: actions/setup-node@v4
         with:
           node-version: 20
-          cache: npm
+          cache: 'pnpm'
 
       - name: Install dependencies
-        run: npm ci
+        run: pnpm install --frozen-lockfile
 
       - name: Build database
-        run: npm run build:db
+        run: pnpm build:db
 
       - name: Compress database
         run: gzip -k -9 public/thptqg2016.db
 
       - name: Build site
-        run: npm run build
+        run: pnpm build
 
       - name: Remove uncompressed db from dist
         run: rm -f dist/thptqg2016.db

2016/package.json

@@ -1,6 +1,7 @@
 {
   "name": "thptqg2016",
   "private": true,
+  "packageManager": "pnpm@11.1.1",
   "version": "1.0.0",
   "type": "module",
   "description": "Tra cứu điểm thi THPT QG 2016 - Hỗ trợ truy vấn SQL tùy chỉnh",