update sync data from site dashboard and testing closing cycles

backend/README.md

@@ -27,7 +27,9 @@ BUH farm visibility is the union of those lists for **confirmed** managed GMs (r
 ## Active site registry
 
 `GET/POST /api/v1/active-sites/` — register farm-location dashboard APIs.  
-`POST /api/v1/active-sites/{id}/sync/` and `POST /api/v1/active-sites/sync-all/` — stubs (`501`) until mirror pull is built.
+`POST /api/v1/active-sites/{id}/sync/` and `POST /api/v1/active-sites/sync-all/` — pull farm `pusat/export` + `pusat/export/iot` into the HQ mirror (ops + IoT).  
+Cron: `manage.py sync_active_sites_from_farm` every 30 minutes when `ACTIVE_SITE_MIRROR_SYNC_ENABLED=true`.  
+If farm rotated `SITE_API_KEY`, re-register the site (or update `ActiveSite.api_key`) so pull auth succeeds.
 
 ## Setup