feat: Enhance booking functionality with invoice management and dashboard summary

- Added customerId to guest booking requests for better identification.
- Implemented new endpoints for managing booking invoices and dashboard summaries.
- Created BookingInvoice and BookingDashboardSummary DTOs to support new features.
- Updated Booking and BookingInvoice models to include payment method and timestamps.
- Enhanced BookingService to handle invoice creation upon payment confirmation.
- Modified BookingRepository to support CRUD operations for BookingInvoice.
- Updated TenantDbContext to include BookingInvoice DbSet and relevant configurations.
- Improved error handling and validation for booking completion and payment processes.

TenantDbContext.cs

@@ -78,6 +78,10 @@ namespace Fitness_core_BE
         // TimeBankCard's own, unrelated RfidTagId string field.
         public DbSet<RfidTag> RfidTags => Set<RfidTag>();
 
+        // Snapshot receipt created whenever a Booking's payment is recorded -- see
+        // Models/BookingInvoice.cs. Deliberately separate from CustomerInvoice (membership-only).
+        public DbSet<BookingInvoice> BookingInvoices => Set<BookingInvoice>();
+
         protected override void OnModelCreating(ModelBuilder modelBuilder)
         {
             base.OnModelCreating(modelBuilder);
@@ -184,6 +188,7 @@ namespace Fitness_core_BE
             modelBuilder.Entity<Facility>().Ignore(f => f.Client);
             modelBuilder.Entity<FacilitySession>().Ignore(s => s.Client);
             modelBuilder.Entity<Booking>().Ignore(b => b.Client);
+            modelBuilder.Entity<BookingInvoice>().Ignore(i => i.Client);
             modelBuilder.Entity<TimeBankCard>().Ignore(t => t.Client);
             modelBuilder.Entity<TimeBankCardUsageLog>().Ignore(l => l.Client);
 
@@ -278,6 +283,9 @@ namespace Fitness_core_BE
             modelBuilder.Entity<Booking>()
                 .HasIndex(b => new { b.FKFacilityId, b.StartTime, b.EndTime });
 
+            modelBuilder.Entity<BookingInvoice>()
+                .HasIndex(i => new { i.FKClientId, i.IssuedAt });
+
             modelBuilder.Entity<UnlinkedDeviceEnrollment>()
                 .HasIndex(e => new { e.FKDeviceId, e.DeviceEmployeeNo, e.LinkedAt });