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.Admin.API/appsettings.json

@@ -0,0 +1,32 @@
+{
+  "Logging": {
+    "LogLevel": {
+      "Default": "Information",
+      "Microsoft.AspNetCore": "Warning"
+    }
+  },
+  "AllowedHosts": "*",
+  "ConnectionStrings": {
+    "DefaultConnection": "Host=localhost;Port=5434;Database=meezi;Username=meezi;Password=meezi_local_pass",
+    "Redis": "localhost:6381"
+  },
+  "Jwt": {
+    "Key": "meezi-dev-secret-key-min-32-chars!!",
+    "Issuer": "meezi",
+    "Audience": "meezi-admin",
+    "AccessTokenExpiryDays": 7,
+    "RefreshTokenExpiryDays": 30
+  },
+  "Cors": {
+    "Origins": [
+      "http://localhost:3000",
+      "http://localhost:3101",
+      "http://localhost:3102",
+      "https://localhost:3000"
+    ]
+  },
+  "Kavenegar": {
+    "ApiKey": "",
+    "OtpTemplate": "verify"
+  }
+}