refactor(runtime): cut graphical host over to canonical root

Make every App composition phase borrow one GameRuntime, retire the duplicate view/event adapters, and dispose the root only after its graphical borrowers release. This preserves synchronous UI commands while giving shutdown one exact ownership ledger.

Co-authored-by: OpenAI Codex <codex@openai.com>

tests/AcDream.App.Tests/Runtime/RuntimeCharacterOwnershipTests.cs

@@ -8,7 +8,15 @@ public sealed class RuntimeCharacterOwnershipTests
         string source = ReadSource("Rendering", "GameWindow.cs");
 
         Assert.Contains(
-            "_runtimeCharacter = new RuntimeCharacterState();",
+            "private readonly GameRuntime _runtime;",
+            source,
+            StringComparison.Ordinal);
+        Assert.Contains(
+            "_runtime = new GameRuntime(new GameRuntimeDependencies(",
+            source,
+            StringComparison.Ordinal);
+        Assert.DoesNotContain(
+            "new RuntimeCharacterState(",
             source,
             StringComparison.Ordinal);
         Assert.DoesNotContain(
@@ -76,7 +84,11 @@ public sealed class RuntimeCharacterOwnershipTests
             inventory,
             StringComparison.Ordinal);
         Assert.Contains(
-            "\"runtime character state\"",
+            "new ResourceShutdownStage(\"game runtime root\"",
+            shutdown,
+            StringComparison.Ordinal);
+        Assert.DoesNotContain(
+            "RuntimeCharacterState Character",
             shutdown,
             StringComparison.Ordinal);
     }