feat(rendering): compare the incremental shadow scene

Construct Slice F's non-drawing scene only for lifecycle automation, drain accepted static and live deltas at the final update boundary, and compare exact current-path fingerprints at cadence and checkpoints. Publish bounded mismatch, journal, index, digest, and memory evidence without changing normal launches or draw submission.

Release: 8,211 passed, 5 skipped.

src/AcDream.App/Rendering/RenderFrameOrchestrator.cs

@@ -91,6 +91,36 @@ internal sealed class NullRenderFramePostDiagnosticsPhase :
     }
 }
 
+/// <summary>
+/// Fixed-order post-diagnostic fan-out. The shadow referee must run before
+/// lifecycle checkpoint publication so each artifact observes the comparison
+/// made against that exact completed render frame.
+/// </summary>
+internal sealed class SerialRenderFramePostDiagnosticsPhase :
+    IRenderFramePostDiagnosticsPhase
+{
+    private readonly IRenderFramePostDiagnosticsPhase[] _phases;
+
+    public SerialRenderFramePostDiagnosticsPhase(
+        params IRenderFramePostDiagnosticsPhase[] phases)
+    {
+        ArgumentNullException.ThrowIfNull(phases);
+        if (phases.Length == 0 || phases.Any(static phase => phase is null))
+        {
+            throw new ArgumentException(
+                "At least one non-null post-diagnostic phase is required.",
+                nameof(phases));
+        }
+        _phases = [.. phases];
+    }
+
+    public void Process(RenderFrameInput input, RenderFrameOutcome outcome)
+    {
+        for (int i = 0; i < _phases.Length; i++)
+            _phases[i].Process(input, outcome);
+    }
+}
+
 /// <summary>
 /// Closes presentation transactions which may have opened before a later
 /// render phase failed. Recovery is idempotent so failures before the