feat(ci): SQLite 每日备份到 NAS(异地容灾,#26/F2)

backup-db.sh:ssh pangolin1 → sqlite3 online .backup 取 WAL 一致快照 + 远端
integrity_check → gzip 流回 → 存 NAS /volume1/docker/backups/pangolin,保留 30 天。
backup.yml:每日 02:00(北京)cron + 手动,ubuntu-latest,复用 DEPLOY_SSH_KEY,
Telegram 通知。异地=家里 NAS≠VPS 机房。不在 pangolin1 装/常驻任何东西。

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

.gitea/workflows/ci.yml

@@ -54,7 +54,8 @@ jobs:
               /mnt/scripts/ci/compile-backend.sh \
               /mnt/scripts/ci/release-server.sh \
               /mnt/scripts/ci/deploy-server.sh \
-              /mnt/scripts/ci/test.sh
+              /mnt/scripts/ci/test.sh \
+              /mnt/scripts/ci/backup-db.sh
 
   # ── Job 2: OpenAPI Sync Check ────────────────────────────────────────────
   openapi-check: