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/RenderFramePreparationControllerTests.cs

@@ -0,0 +1,92 @@
+using AcDream.App.Rendering;
+
+namespace AcDream.App.Tests.Rendering;
+
+public sealed class RenderFramePreparationControllerTests
+{
+    private static readonly RenderFrameInput Input = new(0.25d, 1280, 720);
+
+    [Fact]
+    public void Prepare_PreservesResourcesThenDevToolsThenWeatherOrder()
+    {
+        List<string> calls = [];
+        var resources = new Resources(calls);
+        var devTools = new DevTools(calls);
+        var weather = new Weather(calls);
+        var preparation = new RenderFramePreparationController(
+            resources,
+            devTools,
+            weather);
+
+        preparation.Prepare(Input);
+
+        Assert.Equal(["resources", "devtools-begin", "weather"], calls);
+        Assert.Equal(Input, resources.Input);
+        Assert.Equal((float)Input.DeltaSeconds, devTools.DeltaSeconds);
+        Assert.Equal(Input.DeltaSeconds, weather.DeltaSeconds);
+    }
+
+    [Fact]
+    public void Prepare_DevToolsAreOptionalWithoutChangingRequiredOrder()
+    {
+        List<string> calls = [];
+        var preparation = new RenderFramePreparationController(
+            new Resources(calls),
+            devTools: null,
+            new Weather(calls));
+
+        preparation.Prepare(Input);
+
+        Assert.Equal(["resources", "weather"], calls);
+    }
+
+    [Fact]
+    public void Constructor_RejectsMissingRequiredOwners()
+    {
+        var resources = new Resources([]);
+        var weather = new Weather([]);
+
+        Assert.Throws<ArgumentNullException>(() =>
+            new RenderFramePreparationController(null!, null, weather));
+        Assert.Throws<ArgumentNullException>(() =>
+            new RenderFramePreparationController(resources, null, null!));
+    }
+
+    private sealed class Resources(List<string> calls) : IRenderFrameResourcePhase
+    {
+        public RenderFrameInput Input { get; private set; }
+
+        public void Prepare(RenderFrameInput input)
+        {
+            Input = input;
+            calls.Add("resources");
+        }
+    }
+
+    private sealed class DevTools(List<string> calls) : IDevToolsFrameLifecycle
+    {
+        public float DeltaSeconds { get; private set; }
+
+        public void BeginFrame(float deltaSeconds)
+        {
+            DeltaSeconds = deltaSeconds;
+            calls.Add("devtools-begin");
+        }
+
+        public void AbortFrame() => calls.Add("devtools-abort");
+
+        public void Render(double deltaSeconds, int viewportWidth, int viewportHeight) =>
+            calls.Add("devtools-render");
+    }
+
+    private sealed class Weather(List<string> calls) : IRenderWeatherFramePhase
+    {
+        public double DeltaSeconds { get; private set; }
+
+        public void Tick(double deltaSeconds)
+        {
+            DeltaSeconds = deltaSeconds;
+            calls.Add("weather");
+        }
+    }
+}