profiles: add address management, user edit, fix form redirect

- Add type (Mailing/Billing/Shipping) and isDefault fields to Address
  schema with migration. Unique default enforced server-side.
- Rewrite profiles page with inline address creation form and
  editable user name/email within the profile modal.
- Add upsertAddress and updateUser form actions.
- Fix form redirect by adding use:enhance to AdminForm.
- Disable Update button in AdminForm until a field is changed
  (prevents accidental submissions).

src/lib/svelte-admin/registry.ts

@@ -73,7 +73,7 @@ const models: AdminModelConfig[] = [
 				relationKey: 'addresses',
 				label: 'Addresses',
 				type: 'has-many',
-				displayFields: ['street', 'city', 'state', 'zip']
+				displayFields: ['type', 'street', 'city', 'state', 'postalCode', 'country', 'isDefault']
 			}
 		]
 	},