Make character UI retries transactional

src/AcDream.App/UI/Layout/CharacterManagementUiMountCoordinator.cs

@@ -53,23 +53,42 @@ internal sealed class CharacterManagementUiMountCoordinator : IDisposable
             if (resources is null)
                 return;
 
-            Controller = CharacterManagementUiController.Bind(
+            CharacterManagementUiController? candidate =
+                CharacterManagementUiController.CreateDetached(
                 _host,
                 resources.Layout,
                 resources.TemplateResolver,
                 dialogs,
                 _bindings,
                 resources.Strings);
-            if (Controller is not null)
-            {
-                Console.WriteLine(
-                    $"[UI] retail character management from enum table 5 "
-                    + $"(0x10000005 -> 0x{resources.LayoutId:X8}, "
-                    + "root 0x1000039A; flat list, no viewport).");
-            }
+            if (candidate is null)
+                return;
+
+            // Take ownership before the first attach/tick. Template resolution
+            // happens inside that tick and can throw after the root and button
+            // handlers are live; the catch below can therefore always retire
+            // the exact partial controller before a later retry.
+            Controller = candidate;
+            candidate.AttachAndTick();
+            Console.WriteLine(
+                $"[UI] retail character management from enum table 5 "
+                + $"(0x10000005 -> 0x{resources.LayoutId:X8}, "
+                + "root 0x1000039A; flat list, no viewport).");
         }
         catch (Exception error)
         {
+            CharacterManagementUiController? partial = Controller;
+            Controller = null;
+            try
+            {
+                partial?.Dispose();
+            }
+            catch (Exception cleanupError)
+            {
+                Console.WriteLine(
+                    "[UI] character management partial-mount cleanup failed: "
+                    + cleanupError.Message);
+            }
             Console.WriteLine(
                 "[UI] character management mount will retry after resource "
                 + $"recovery: {error.Message}");