devops: 备案通过回切 https 域名 + 流水线 Ali 单轨

- nginx-jiu-ali.conf：443 ssl+http2 正式入口（HSTS/XFO/nosniff 安全头、
  ACME webroot 续期通道、80→443 跳转）；8443 明文过渡口拆除
- 客户端构建 URL 全量回切 https://jiu.51yanmei.com（compile×5/local_test/
  release-client/notify）
- 流水线去 EC2：deploy-client/site 单轨 Ali、manual 回滚与每日备份切 ali、
  seed/reset/debug-db 改容器内取密码（SEC-003，退役 DB_PASSWORD secret）

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01JJ1g8XV1YhhmHRzhwWEW7o

.gitea/workflows/backup.yml

@@ -18,9 +18,10 @@ jobs:
 
       - name: Dump MySQL to local backup dir
         env:
-          EC2_SSH_KEY: ${{ secrets.EC2_SSH_KEY }}
-          EC2_HOST: ${{ secrets.EC2_HOST }}
-          EC2_USER: ${{ secrets.EC2_USER }}
+          # 2026-07-03 割接后备份源=阿里机主库
+          DEPLOY_SSH_KEY: ${{ secrets.ALI_SSH_KEY }}
+          DEPLOY_HOST: ${{ secrets.ALI_HOST }}
+          DEPLOY_USER: ${{ secrets.ALI_USER }}
         run: sh scripts/ci/backup-db.sh
 
       - name: Notify (Telegram)