Add table mappings and navigation property updates

Added `[Table]` attributes to `Connection`, `Endpoint`, `EndpointAuth`, and `Profile` classes to define database table mappings. Updated `Profile` with schema information.

Introduced a `Profile` navigation property in `RecAction` with a `[ForeignKey]` attribute to establish a relationship with the `Profile` entity. Temporarily marked it as `[NotMapped]` due to a foreign key type mismatch, with a `TODO` to resolve this in the future.

Included `System.ComponentModel.DataAnnotations.Schema` in `using` directives to support these changes.

src/ReC.Domain/Entities/Connection.cs

@@ -1,5 +1,4 @@
-using System;
+using System.ComponentModel.DataAnnotations;
-using System.ComponentModel.DataAnnotations;
 using System.ComponentModel.DataAnnotations.Schema;
 
 namespace ReC.Domain.Entities;

src/ReC.Domain/Entities/Endpoint.cs

@@ -1,5 +1,4 @@
-using System;
+using System.ComponentModel.DataAnnotations;
-using System.ComponentModel.DataAnnotations;
 using System.ComponentModel.DataAnnotations.Schema;
 
 namespace ReC.Domain.Entities;

src/ReC.Domain/Entities/EndpointAuth.cs

@@ -1,5 +1,4 @@
-using System;
+using System.ComponentModel.DataAnnotations;
-using System.ComponentModel.DataAnnotations;
 using System.ComponentModel.DataAnnotations.Schema;
 
 namespace ReC.Domain.Entities;

src/ReC.Domain/Entities/Profile.cs

@@ -1,5 +1,4 @@
-using System;
+using System.ComponentModel.DataAnnotations;
-using System.ComponentModel.DataAnnotations;
 using System.ComponentModel.DataAnnotations.Schema;
 
 namespace ReC.Domain.Entities;

src/ReC.Domain/Entities/RecAction.cs

@@ -13,6 +13,8 @@ public class RecAction
     [Column("PROFILE_ID")]
     public long? ProfileId { get; set; }
 
+    // TODO: Remove [NotMapped] once ProfileId FK type mismatch is resolved.
+    [NotMapped]
     [ForeignKey("ProfileId")]
     public Profile? Profile { get; set; }