[fix] CI の bun インストールを oven-sh/setup-bun に変更

proto の bun プラグインが CI 環境のバージョンで
.prototools のスキーマを認識できないため、
公式アクション oven-sh/setup-bun@v2 に切り替え

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: makinzm

.github/workflows/docs.yml

@@ -25,24 +25,18 @@ jobs:
       - name: Setup Pages
         uses: actions/configure-pages@v5
 
-      - name: Install proto
-        run: |
-          curl -fsSL https://moonrepo.dev/install/proto.sh | bash
-          echo "$HOME/.proto/bin" >> "$GITHUB_PATH"
-
-      - name: Install bun via proto
-        working-directory: website
-        run: |
-          proto install bun
-          proto install node
+      - name: Setup Bun
+        uses: oven-sh/setup-bun@v2
+        with:
+          bun-version: "1.3.11"
 
       - name: Install dependencies
         working-directory: website
-        run: proto run bun -- install
+        run: bun install
 
       - name: Build Starlight site
         working-directory: website
-        run: proto run bun -- run build
+        run: bun run build
 
       - name: Upload Pages artifact
         uses: actions/upload-pages-artifact@v3