fix(backend): make API types internal

backend/src/Socialize.Api/Modules/Campaigns/Handlers/CreateCampaign.cs

@@ -6,7 +6,7 @@ using Socialize.Api.Modules.Campaigns.Data;
 
 namespace Socialize.Api.Modules.Campaigns.Handlers;
 
-public record CreateCampaignRequest(
+internal record CreateCampaignRequest(
     Guid WorkspaceId,
     Guid ClientId,
     string Name,
@@ -15,7 +15,7 @@ public record CreateCampaignRequest(
     string? Description,
     string? Notes);
 
-public class CreateCampaignRequestValidator
+internal class CreateCampaignRequestValidator
     : Validator<CreateCampaignRequest>
 {
     public CreateCampaignRequestValidator()
@@ -32,7 +32,7 @@ public class CreateCampaignRequestValidator
     }
 }
 
-public class CreateCampaignHandler(
+internal class CreateCampaignHandler(
     AppDbContext dbContext,
     AccessScopeService accessScopeService)
     : Endpoint<CreateCampaignRequest, CampaignDto>