fix: Store service prices in cents and fix contracts permission

- Update Service model to use price_cents/deposit_amount_cents as IntegerField
- Add @property methods for backward compatibility (price, deposit_amount return dollars)
- Update ServiceSerializer to convert dollars <-> cents on read/write
- Add migration to convert column types from numeric to integer
- Fix BusinessEditModal to properly use typed PlatformBusiness interface
- Add missing feature permission fields to PlatformBusiness TypeScript interface

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontend/src/api/platform.ts

@@ -33,6 +33,24 @@ export interface PlatformBusiness {
   can_use_custom_domain: boolean;
   can_white_label: boolean;
   can_api_access: boolean;
+  // Feature permissions (optional - returned by API but may not always be present in tests)
+  can_add_video_conferencing?: boolean;
+  can_connect_to_api?: boolean;
+  can_book_repeated_events?: boolean;
+  can_require_2fa?: boolean;
+  can_download_logs?: boolean;
+  can_delete_data?: boolean;
+  can_use_sms_reminders?: boolean;
+  can_use_masked_phone_numbers?: boolean;
+  can_use_pos?: boolean;
+  can_use_mobile_app?: boolean;
+  can_export_data?: boolean;
+  can_use_plugins?: boolean;
+  can_use_tasks?: boolean;
+  can_create_plugins?: boolean;
+  can_use_webhooks?: boolean;
+  can_use_calendar_sync?: boolean;
+  can_use_contracts?: boolean;
 }
 
 export interface PlatformBusinessUpdate {