feat(objects): DiscoverConstructibleTypes — all constructible Item/Mobile types

Implement DiscoverConstructibleTypes() method with HasConstructibleCtor helper
to enumerate every non-abstract Item/Mobile subclass in AssemblyHandler.Assemblies
that has at least one [Constructible] ctor.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Projects/UOContent.Tests/Tests/Commands/Objects/ObjectDiscoveryTests.cs

@@ -0,0 +1,19 @@
+using Server.Commands;
+using Server.Items;
+using Xunit;
+
+namespace UOContent.Tests.Commands.Objects;
+
+[Collection("Sequential UOContent Tests")]
+public class ObjectDiscoveryTests
+{
+    [Fact]
+    public void Discover_includes_concrete_constructibles_and_excludes_abstract()
+    {
+        var types = ObjectIntrospection.DiscoverConstructibleTypes();
+
+        Assert.Contains(typeof(Katana), types);
+        Assert.Contains(typeof(Runebook), types);
+        Assert.DoesNotContain(typeof(BaseWeapon), types); // abstract
+    }
+}

Projects/UOContent/Commands/Object Creation/ObjectIntrospection.cs

@@ -184,4 +184,45 @@ public static class ObjectIntrospection
 
         return lines;
     }
+
+    public static List<Type> DiscoverConstructibleTypes()
+    {
+        var results = new List<Type>();
+
+        foreach (var asm in AssemblyHandler.Assemblies)
+        {
+            foreach (var type in AssemblyHandler.GetTypeCache(asm).Types)
+            {
+                if (type.IsAbstract)
+                {
+                    continue;
+                }
+
+                if (!typeof(Item).IsAssignableFrom(type) && !typeof(Mobile).IsAssignableFrom(type))
+                {
+                    continue;
+                }
+
+                if (HasConstructibleCtor(type))
+                {
+                    results.Add(type);
+                }
+            }
+        }
+
+        return results;
+    }
+
+    private static bool HasConstructibleCtor(Type type)
+    {
+        foreach (var ctor in type.GetConstructors())
+        {
+            if (Attributes.IsConstructible(ctor, AccessLevel.Developer))
+            {
+                return true;
+            }
+        }
+
+        return false;
+    }
 }