Phase 4: Webhooks, Backup/Restore UI, Onboarding/Tutorial

- Webhooks Backend: model, schema, service (HMAC-SHA256, httpx), routes, event bus dispatcher, migration 0042
- Webhooks Frontend: SettingsWebhooksPage (CRUD, test button, event multi-select), API client
- Backup/Restore Backend: model, schema, service (pg_dump/pg_restore), routes (admin-only), migration 0043
- Backup/Restore Frontend: SettingsBackupPage (create, list, restore dialog with RESTORE confirmation, auto-refresh)
- Onboarding: OnboardingTour (8 steps, custom CSS overlay), WelcomeDialog, onboardingStore (zustand + localStorage)
- Onboarding integrated into AppShell
- Routes: /settings/webhooks, /settings/backup registered
- Settings nav: Webhooks, Backup & Restore entries added
- Migration conflict fixed: 0042_webhooks → 0043_backups chain

app/models/__init__.py

@@ -21,7 +21,9 @@ from app.models.system_settings import SystemSettings
 from app.models.tax import TaxRate
 from app.models.tenant import Tenant
 from app.models.user import User, UserTenant
+from app.models.backup import Backup
 from app.models.custom_field_definition import CustomFieldDefinition
+from app.models.webhook import Webhook
 from app.models.workflow import Workflow, WorkflowInstance, WorkflowStepHistory
 
 __all__ = [
@@ -55,7 +57,9 @@ __all__ = [
     "PluginMigration",
     "AIConversation",
     "AIMessage",
+    "Backup",
     "CustomFieldDefinition",
+    "Webhook",
     "Workflow",
     "WorkflowInstance",
     "WorkflowStepHistory",