feat(tui): add SLA reporting view

Full-screen SLA report accessible via [s] from detail panel.
Computes uptime%, downtime, outage count, longest outage, MTTR,
and MTBF from state_changes table. Includes daily breakdown with
bar chart, switchable time periods (24h/7d/30d/90d), and
scrollable viewport. LATE/STALE treated as UP for SLA purposes.

.gitea/workflows/ci.yml

@@ -1,6 +1,8 @@
 name: CI
 
 on:
+  push:
+    branches: [main]
   pull_request:
 
 env: