feat: 将本地独有功能移植到 upstream 最新版本

基于 upstream/master (c5922f9) 新建分支，移植以下功能：
1. 扫码登录（DyQrCodeService + ConfigController 3个接口）
2. 视频预览组件（VideoPlayer.vue）
3. 下载配置服务（DownloadConfigService + AppConfig 6个扩展字段）
4. Gitea CI/CD（.gitea/workflows/deploy.yml）
5. 生产 Dockerfile（Dockerfile.prod，含中国镜像源配置）

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

.gitea/workflows/deploy.yml

@@ -0,0 +1,47 @@
+name: 部署到群晖
+
+on:
+  push:
+    branches: [main]
+
+jobs:
+  deploy:
+    runs-on: ubuntu-latest
+    steps:
+      - name: 安装 Docker CLI
+        run: |
+          # 替换 Debian 源为清华镜像，避免国内连 deb.debian.org 超时
+          sed -i 's|deb.debian.org|mirrors.tuna.tsinghua.edu.cn|g' /etc/apt/sources.list /etc/apt/sources.list.d/*.list 2>/dev/null || true
+          sed -i 's|security.debian.org|mirrors.tuna.tsinghua.edu.cn/debian-security|g' /etc/apt/sources.list /etc/apt/sources.list.d/*.list 2>/dev/null || true
+          apt-get update -qq
+          apt-get install -y -qq docker.io
+
+      - name: 拉取代码
+        uses: actions/checkout@v4
+
+      - name: 构建镜像
+        run: docker build -f Dockerfile.prod -t dysync:latest .
+
+      - name: 停止旧容器
+        run: |
+          docker stop dysync 2>/dev/null || true
+          docker rm dysync 2>/dev/null || true
+
+      - name: 启动新容器
+        run: |
+          docker run -d \
+            --name dysync \
+            --restart unless-stopped \
+            -p 10101:10101 \
+            -e TZ=Asia/Shanghai \
+            -e ASPNETCORE_ENVIRONMENT=Production \
+            -v /volume1/docker/apps/dysync/db:/app/db \
+            -v /volume1/docker/apps/dysync/logs:/app/logs \
+            -v /volume2/save/dysync/collect:/app/collect \
+            -v /volume2/save/dysync/favorite:/app/favorite \
+            -v /volume2/save/dysync/uper:/app/uper \
+            dysync:latest
+
+      - name: 部署完成提示
+        run: |
+          echo "✅ 部署完成，浏览器访问 http://192.168.1.66:10101 查看"