alex
19242b4152
feat: notification center toast coordination (PR-4)
- EventToastBridge checks notification_toast_level and notification_mute_categories
- toast-rules.ts: event-to-category/severity mapping functions
- Settings page: notification preferences section (toast level dropdown, mute checkboxes)
- Settings API types extended with notification preference fields
- 17 frontend tests (toast-rules + bridge)
- Preference hierarchy: mute categories → toast level → show/hide
Quality gates: vitest 17 passed, tsc clean, eslint clean