feat: add separate pages-dev-server background job

- Create dedicated pages-dev-server job that runs bun pages:dev
- Runs in parallel with incremental-build as a background task
- Uses bun for faster package management and dev server execution
- Includes proper dependency installation and Node.js setup

🤖 Generated with [Claude Code](https://claude.ai/code)

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

.github/workflows/release-pages.yml

@@ -14,6 +14,35 @@ on:
   workflow_dispatch:
 
 jobs:
+  pages-dev-server:
+    runs-on: ubuntu-latest
+    if: github.event_name == 'workflow_dispatch' || github.event_name == 'push' || github.event.workflow_run.conclusion == 'success'
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v5
+
+      - name: Install bun
+        uses: oven-sh/setup-bun@v2
+        with:
+          bun-version: latest
+
+      - name: Install pnpm
+        uses: pnpm/action-setup@v4
+        with:
+          version: 10
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v5
+        with:
+          node-version: '24'
+          cache: 'pnpm'
+
+      - name: Install dependencies
+        run: pnpm install --frozen-lockfile
+
+      - name: Run pages dev server
+        run: bun pages:dev
+
   incremental-build:
     runs-on: ubuntu-latest
     # Only run if the triggering workflow succeeded (or manual dispatch/push)