fix(oci): remove everything an OCI installation leaves, and name cluster events

AppImage/scripts/notification_events.py

@@ -4367,8 +4367,9 @@ class ProxmoxHookWatcher:
         # "🔵 constructor: Problema del sistema detectado" / "+1 problema
         # más del sistema (Problemas adicionales: - problema_del_sistema)"
         # messages the operator sees on Telegram. Preserve the PVE payload
-        # as `reason` so both surfaces have concrete text to render.
-        if event_type == 'system_problem':
+        # as `reason` so both surfaces have concrete text to render. A cluster
+        # event (fencing) renders it too: the message is what happened.
+        if event_type in ('system_problem', 'split_brain'):
             reason_text = (message or title or '').strip()
             if reason_text:
                 data['reason'] = reason_text[:500]

AppImage/scripts/notification_templates.py

@@ -1218,7 +1218,7 @@ TEMPLATES = {
     # ── Cluster events ──
     'split_brain': {
         'title': '{hostname}: Cluster event reported',
-        'body': 'A cluster event was reported. Review cluster status and the source event for details.',
+        'body': 'A cluster event was reported:\n{reason}',
         'label': 'Cluster event',
         'group': 'cluster',
         'default_enabled': True,