chore: upgrade deps and GitHub Actions for Node.js 24 (#889)

chore: upgrade dependencies and GitHub Actions for Node.js 24 compatibility

Upgrade GitHub Actions to fix Node.js 20 deprecation warnings:
- actions/checkout v4 → v6
- actions/setup-node v4 → v6
- pnpm/action-setup v3 → v4
- docker/login-action v3 → v4
- docker/setup-qemu-action v3 → v4
- docker/setup-buildx-action v3 → v4
- docker/build-push-action v5 → v7
- node-version 20 → 22, pnpm 8 → 10

Upgrade project dependencies:
- frontend: vue 3.5.30, naive-ui 2.44.1, dompurify 3.3.3, @unhead/vue 2.1.12
- worker: hono 4.12.7, @cloudflare/workers-types, typescript-eslint 8.57.0
- all: wrangler 4.72.0

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

.github/workflows/sync.yaml

@@ -12,7 +12,7 @@ jobs:
     if: ${{ github.event.repository.fork }}
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
 
       - name: Sync upstream changes
         id: sync