feat(alert): add Opsgenie provider

Support Opsgenie Alert API v2 with US/EU endpoint selection,
configurable priority (P1-P5), and GenieKey auth. TUI form
includes API key, priority picker, and EU instance toggle.

.gitea/workflows/ci.yml

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