feat: add recurring bookings feature with related handlers and services

- Introduced recurring booking groups with the ability to create and cancel them.
- Added database migrations for recurring bookings, including new tables and relationships.
- Implemented handlers for creating and canceling recurring bookings in the admin booking module.
- Enhanced existing booking services to support recurring bookings logic.
- Updated API contract to include new schemas for recurring bookings.
- Refactored existing code for improved readability and maintainability.

apps/backend/test/plan/plan-pricing.service.test.ts

@@ -14,6 +14,7 @@ function makeV1Rules(): PlanRules {
       publicBookingPage: false,
       advancedReports: false,
       whatsappReminders: false,
+      fixedSlots: false,
     },
   };
 }
@@ -28,6 +29,7 @@ function makeV2Rules(overrides?: Record<string, { amount: number; currency: stri
       publicBookingPage: true,
       advancedReports: true,
       whatsappReminders: true,
+      fixedSlots: true,
     },
     ...(overrides ? { pricing: { overrides } } : {}),
   };