feat: stack glob patterns and route severity levels (#1651)

* feat: add stack glob patterns and route severity levels

Operators can filter notification routes and mute rules with anchored * globs, and routes can target info, warning, or error. Matching is fail-closed for unsafe stored patterns; write paths keep partial-PUT semantics and ReDoS caps.

* test: split mute and routing chip tests to avoid dialog race

* fix: move stack pattern client validator out of PatternChips

* fix: bound stack glob matching and atomic pattern chip saves

backend/src/__tests__/notification-channels.test.ts

@@ -134,6 +134,7 @@ describe('Apprise channel helpers', () => {
       stack_patterns: [],
       label_ids: null,
       categories: null,
+      levels: null,
       channel_type: 'apprise',
       channel_url: 'http://apprise.local/notify/path-secret',
       config: JSON.stringify({ tags: 'ops' }),