(feature) Add live refresh for run detail status

Add a server-rendered run detail partial and a small vanilla JavaScript
refresh hook so active backup runs update status, controls, timing, and
rsync log output without a full page reload.

Document the Django-template-first refresh pattern for future control
panel work.

Refs #36

docs/development.md

@@ -50,6 +50,16 @@ python3 manage.py showmigrations pobsync_backend
 The short `pobsync` aliases are limited to operational actions that are useful while debugging a running install.
 Configuration aliases are intentionally not public commands; use the Django UI or explicit management commands instead.
 
+## UI Refresh Pattern
+
+The control panel stays Django-template-first. Pages that need live status should expose a small server-rendered partial
+view and opt into refresh with `data-refresh-url` and `data-refresh-interval` on the container that should be replaced.
+The shared script in `base.html` polls only those explicit regions, skips refreshes while the browser tab is hidden, and
+lets the partial response turn polling off with the `X-Pobsync-Refresh-Active: false` header.
+
+Use this for operational status surfaces such as running backup details. Avoid refreshing form-heavy sections while an
+operator might be typing.
+
 Worker and scheduler commands are normally run by systemd services:
 
 ```