feat(api): .NET 10 multi-tenant REST API

Full backend implementation:
- Multi-tenant cafe/restaurant management (menus, orders, tables, staff)
- POS order flow with ZarinPal and Snappfood payment integration
- OTP authentication via Kavenegar SMS
- QR digital menu with public discover/finder endpoints
- Customer loyalty, coupons, CRM
- PostgreSQL via EF Core, Redis for caching/sessions
- Background jobs, webhook handlers
- Full migration history

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

src/Meezi.Core/Entities/SubscriptionPayment.cs

@@ -0,0 +1,17 @@
+using Meezi.Core.Enums;
+
+namespace Meezi.Core.Entities;
+
+public class SubscriptionPayment : TenantEntity
+{
+    public PlanTier PlanTier { get; set; }
+    public int Months { get; set; }
+    public decimal AmountToman { get; set; }
+    public long AmountRials { get; set; }
+    public PaymentProvider Provider { get; set; } = PaymentProvider.ZarinPal;
+    public string? Authority { get; set; }
+    public string? RefId { get; set; }
+    public SubscriptionPaymentStatus Status { get; set; } = SubscriptionPaymentStatus.Pending;
+
+    public Cafe Cafe { get; set; } = null!;
+}