CI: use Node.js over bun

.github/workflows/main.yml

@@ -15,9 +15,15 @@ jobs:
         uses: actions/checkout@v4
         with:
           persist-credentials: false
-      - uses: oven-sh/setup-bun@v2
+      - uses: pnpm/action-setup@v4
+        name: Install pnpm
         with:
-          bun-version: canary
+            run_install: false
+      - name: Use Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version-file: '.node-version'
+          cache: 'pnpm'
       - name: Get current date
         id: date
         run: |
@@ -43,8 +49,9 @@ jobs:
             ${{ runner.os }}-v3-${{ steps.date.outputs.year }}-${{ steps.date.outputs.month }}-
             ${{ runner.os }}-v3-${{ steps.date.outputs.year }}-
             ${{ runner.os }}-v3-
-      - run: bun install
-      - run: bun run build
+      - name: Install dependencies
+        run: pnpm install
+      - run: pnpm run build
       - name: Pre-deploy check
         # If the public directory doesn't exist, the build should fail.
         # If the public directory is empty, the build should fail.