Update low-code docs: foreign key API & wording

Reflect API and copy updates in low-code docs. foreign-access.md: replace ConfigureProperty/SetForeignKey example with entity.AddOrGetProperty and assignment of a ForeignKeyDescriptor (EntityName, DisplayPropertyName, Access). index.md: minor wording tweaks for clarity and a corrected link anchor to the three-layer configuration system. model-json.md: remove the empty "foreignKeys" array from the entity JSON example to avoid implying it's required.

docs/en/low-code/foreign-access.md

@@ -39,10 +39,13 @@ AbpDynamicEntityConfig.EntityConfigurations.Configure(
     "MyApp.Orders.Order",
     entity =>
     {
-        entity.ConfigureProperty("CustomerId", prop =>
+        var customerIdProperty = entity.AddOrGetProperty("CustomerId");
+        customerIdProperty.ForeignKey = new ForeignKeyDescriptor
         {
-            prop.SetForeignKey("MyApp.Customers.Customer", "Name", ForeignAccess.Edit);
-        });
+            EntityName = "MyApp.Customers.Customer",
+            DisplayPropertyName = "Name",
+            Access = ForeignAccess.Edit
+        };
     }
 );
 ````

docs/en/low-code/index.md

@@ -7,7 +7,7 @@
 
 # Low-Code System
 
-The ABP Low-Code System lets you define entities using C# attributes or Fluent API and automatically generates:
+The ABP Low-Code System allows you to define entities using C# attributes or Fluent API and automatically generates:
 
 * **Database tables** (via EF Core migrations)
 * **CRUD REST APIs** (Get, GetList, Create, Update, Delete)
@@ -19,7 +19,7 @@ No need to write entity classes, DTOs, application services, repositories, or UI
 
 ## Why Low-Code?
 
-Traditionally, adding a new entity to an ABP application requires:
+Traditionally, adding a new entity with full CRUD functionality to an ABP application requires:
 
 1. Entity class in Domain
 2. DbContext configuration in EF Core
@@ -157,7 +157,7 @@ Alternatively, define entities in a JSON file without writing C# classes:
 
 See [model.json Structure](model-json.md) for the full specification.
 
-> Both approaches can be combined. The [three-layer configuration system](fluent-api.md#configuration-priority) merges Attributes, JSON, and Fluent API with clear priority rules.
+> Both approaches can be combined. The [three-layer configuration system](fluent-api.md#three-layer-configuration-system) merges Attributes, JSON, and Fluent API with clear priority rules.
 
 ## Key Features
 

docs/en/low-code/model-json.md

@@ -88,7 +88,6 @@ Each entity has the following structure:
   "displayProperty": "Name",
   "parent": null,
   "properties": [],
-  "foreignKeys": [],
   "interceptors": [],
   "ui": {}
 }