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/schemas/backup.py

@@ -0,0 +1,31 @@
+"""Pydantic schemas for Backup CRUD."""
+
+from __future__ import annotations
+
+import uuid
+from datetime import datetime
+
+from pydantic import BaseModel, ConfigDict
+
+
+class BackupResponse(BaseModel):
+    """Schema for returning a backup record."""
+
+    model_config = ConfigDict(from_attributes=True)
+
+    id: uuid.UUID
+    tenant_id: uuid.UUID
+    filename: str
+    size_bytes: int | None = None
+    status: str  # pending, completed, failed
+    error_message: str | None = None
+    created_by: uuid.UUID | None = None
+    created_at: datetime
+    completed_at: datetime | None = None
+
+
+class BackupListResponse(BaseModel):
+    """Schema for listing backups."""
+
+    backups: list[BackupResponse]
+    total: int