The MessageSystem is based on Subject instead of Content (just semantics)

src/Web/Messages/Handlers/PostMessage.cs

@@ -5,7 +5,7 @@ using Hutopy.Web.Messages.Data;
 namespace Hutopy.Web.Messages.Handlers;
 
 public record PostMessageRequest(
-    Guid ContentId,
+    Guid SubjectId,
     string Message);
 
 public class PostMessage(
@@ -25,7 +25,7 @@ public class PostMessage(
     {
         await context.Messages.AddAsync(
             new Message { 
-                ContentId = req.ContentId, 
+                SubjectId = req.SubjectId, 
                 CreatedBy = User.GetUserId(),
                 Value = req.Message },
             ct);