Implement store credit tracking and enforcement

Introduced StoreCreditMovement entity and migration to track store credit usage and settlements. Updated payment flow to enforce credit limits and record credit movements. Modified outstanding balance calculation to use credit movements. Enhanced frontend to display real-time credit info and prevent over-credit payments. Updated API types, seed data, and DI registrations accordingly.

Distribution/Program.cs

@@ -100,6 +100,7 @@ builder.Services.AddScoped<IBankAccountRepository, BankAccountRepository>();
 builder.Services.AddScoped<IChequeBookRepository, ChequeBookRepository>();
 builder.Services.AddScoped<IReceivedChequeRepository, ReceivedChequeRepository>();
 builder.Services.AddScoped<ISupplierPaymentRepository, SupplierPaymentRepository>();
+builder.Services.AddScoped<Distribution.Features.StoreCredit.IStoreCreditMovementRepository, Distribution.Features.StoreCredit.StoreCreditMovementRepository>();
 
 builder.Services.AddScoped<RegionService>();
 builder.Services.AddScoped<RouteService>();