refactor(render): compose render frame orchestrator

Move the accepted draw transaction and failure recovery behind typed frame-phase owners so GameWindow only supplies immutable frame input. Preserve retail draw order, make ImGui/bootstrap shutdown ownership explicit, and restore exact text-render GL state on failures.\n\nCo-authored-by: Codex <codex@openai.com>

tests/AcDream.App.Tests/Rendering/DevToolsFramePresenterTests.cs

@@ -42,8 +42,10 @@ public sealed class DevToolsFramePresenterTests
         var commands = new RecordingCommandSource { Current = first };
         var presenter = Create(backend, commands: commands);
 
+        presenter.BeginFrame(0.1f);
         presenter.Render(0.1, 800, 600);
         commands.Current = second;
+        presenter.BeginFrame(0.2f);
         presenter.Render(0.2, 800, 600);
 
         Assert.Same(first, backend.Contexts[0].Commands);
@@ -60,6 +62,7 @@ public sealed class DevToolsFramePresenterTests
         var panels = new RecordingPanels();
         var presenter = Create(backend, panels: panels);
 
+        presenter.BeginFrame(0.1f);
         presenter.Render(0.1, 1920, 1080);
 
         Assert.Equal(
@@ -93,6 +96,7 @@ public sealed class DevToolsFramePresenterTests
         var camera = new RecordingCamera { IsFlyMode = true, CollideCamera = true };
         var presenter = Create(backend, camera: camera);
 
+        presenter.BeginFrame(0.1f);
         presenter.Render(0.1, 1280, 720);
 
         Assert.Equal(1, camera.ToggleCount);
@@ -113,6 +117,7 @@ public sealed class DevToolsFramePresenterTests
 
         presenter.ToggleSettingsPanel();
         presenter.ResetLayout(1280, 720, DevToolsPanelLayoutCondition.FirstUseEver);
+        presenter.BeginFrame(0.1f);
         presenter.Render(0.1, 1280, 720);
 
         Assert.DoesNotContain(DevToolsPanelKind.Settings, panels.Toggles);
@@ -156,6 +161,68 @@ public sealed class DevToolsFramePresenterTests
                 call.WithoutCondition()));
     }
 
+    [Fact]
+    public void AbortFrame_ClosesAnOpenBackendFrameAndAllowsTheNextFrame()
+    {
+        var calls = new List<string>();
+        var backend = new RecordingBackend(calls);
+        var presenter = Create(backend);
+
+        presenter.BeginFrame(0.1f);
+        presenter.AbortFrame();
+        presenter.AbortFrame();
+        presenter.BeginFrame(0.2f);
+        presenter.Render(0.2, 800, 600);
+
+        Assert.Equal(1, calls.Count(call => call == "abort"));
+        Assert.Equal(2, calls.Count(call => call.StartsWith("begin:")));
+        Assert.Equal(1, calls.Count(call => call == "draw-data"));
+    }
+
+    [Fact]
+    public void RenderFailure_RemainsAbortableAndDoesNotPoisonTheNextFrame()
+    {
+        var calls = new List<string>();
+        var backend = new RecordingBackend(calls)
+        {
+            DrawFailure = new InvalidOperationException("draw"),
+        };
+        var presenter = Create(backend);
+
+        presenter.BeginFrame(0.1f);
+        Assert.Throws<InvalidOperationException>(() =>
+            presenter.Render(0.1, 800, 600));
+        presenter.AbortFrame();
+
+        backend.DrawFailure = null;
+        presenter.BeginFrame(0.2f);
+        presenter.Render(0.2, 800, 600);
+
+        Assert.Equal(0, calls.Count(call => call == "abort"));
+        Assert.Equal(2, calls.Count(call => call == "draw-data"));
+    }
+
+    [Fact]
+    public void BeginFailure_RemainsAbortableAndDoesNotPoisonTheNextFrame()
+    {
+        var calls = new List<string>();
+        var backend = new RecordingBackend(calls)
+        {
+            BeginFailure = new InvalidOperationException("begin"),
+        };
+        var presenter = Create(backend);
+
+        Assert.Throws<InvalidOperationException>(() => presenter.BeginFrame(0.1f));
+        presenter.AbortFrame();
+
+        backend.BeginFailure = null;
+        presenter.BeginFrame(0.2f);
+        presenter.Render(0.2, 800, 600);
+
+        Assert.Equal(1, calls.Count(call => call == "abort"));
+        Assert.Equal(2, calls.Count(call => call.StartsWith("begin:")));
+    }
+
     [Fact]
     public void InputFacingActionsDelegateToTheTypedPanelOwner()
     {
@@ -198,7 +265,7 @@ public sealed class DevToolsFramePresenterTests
                 field => field.FieldType == typeof(Silk.NET.Windowing.IWindow));
         }
 
-        Assert.False(typeof(IDisposable).IsAssignableFrom(
+        Assert.True(typeof(IDisposable).IsAssignableFrom(
             typeof(ImGuiDevToolsFrameBackend)));
     }
 
@@ -221,8 +288,29 @@ public sealed class DevToolsFramePresenterTests
         public List<(string Label, string? Shortcut, bool Selected)> MenuItems { get; } = [];
         public List<PanelContext> Contexts { get; } = [];
         public List<LayoutCallWithCondition> Layouts { get; } = [];
+        public Exception? BeginFailure { get; set; }
+        public Exception? DrawFailure { get; set; }
 
-        public void BeginFrame(float deltaSeconds) => calls.Add($"begin:{deltaSeconds}");
+        public bool ControllerFrameOpen { get; private set; }
+
+        public void BeginFrame(float deltaSeconds)
+        {
+            calls.Add($"begin:{deltaSeconds}");
+            ControllerFrameOpen = true;
+            if (BeginFailure is not null)
+                throw BeginFailure;
+        }
+
+        public void AbortFrame()
+        {
+            // Silk ImGuiController.Render is idempotent. It closes an active
+            // controller frame, but is a no-op if Render already cleared its
+            // private _frameBegun flag before a GL upload failure.
+            if (!ControllerFrameOpen)
+                return;
+            ControllerFrameOpen = false;
+            calls.Add("abort");
+        }
 
         public bool BeginMainMenuBar()
         {
@@ -254,7 +342,14 @@ public sealed class DevToolsFramePresenterTests
             calls.Add($"panels:{context.DeltaSeconds}");
         }
 
-        public void RenderDrawData() => calls.Add("draw-data");
+        public void RenderDrawData()
+        {
+            Assert.True(ControllerFrameOpen);
+            ControllerFrameOpen = false;
+            calls.Add("draw-data");
+            if (DrawFailure is not null)
+                throw DrawFailure;
+        }
 
         public void SetWindowLayout(
             string title,