Move RGBA image contract to model

docs/PROJECT-STRUCTURE.md

@@ -169,6 +169,9 @@ simple hosts. `engine/Age.Engine/Hosting/IMovieHost.cs` owns ordinary, positione
 and modal movie playback contracts. `IHost` inherits all four focused contracts; their required and default
 behavior is unchanged. The neutral `engine/Age.Engine/Model/MovieMaskTransitionRequest.cs` record carries movie
 mask work between the VM, host, and retained graphics without making `Model` depend on `Hosting`.
+`engine/Age.Engine/Model/RgbaImage.cs` owns the format-independent packed RGBA image transported between SYS4
+decoders, host surfaces, renderers, persistence, and tests; consumers do not depend on `Sys4` merely to exchange
+decoded pixels.
 
 `engine/Age.Engine/Model/GfxState.cs` retains cross-domain retained-graphics coordination.
 `engine/Age.Engine/Model/GfxState.Contracts.cs` owns its public render, transition, diagnostic, persistence,

docs/remake-architecture-and-roadmap.md

@@ -781,6 +781,11 @@ do not mix mechanical moves with semantic changes.
    removing the two now-unused imports eliminates `GfxState`'s reverse dependency on the host namespace. Runtime
    validation remains green.
 
+   The fifth bounded contract slice moved the unchanged, format-independent `RgbaImage` record from the SYS4 AGF
+   decoder file into `Model`. Decoders, renderers, persistence, Godot, tests, and the aggregate host now consume
+   the neutral image contract; image-only format imports were removed while genuine SYS4 consumers retained
+   theirs. Decoder and image behavior remain unchanged, and runtime validation remains green.
+
 4. **Make the build graph express source ownership.** Stop linking production `.cs` files from `godot/` and
    `tools/movie-corpus-gate/` into `Age.Engine.Tests`. Extract the platform-neutral frontend/movie/diagnostic
    code into a small production project referenced by Godot, tests, and the corpus gate. Retain both existing
@@ -1141,8 +1146,8 @@ layer's rendering diverges from ADV; save layout.
 ## 8. Immediate next step
 Continue step 3 of the **codebase consolidation** maintenance slice: clarify runtime contracts without changing
 behavior or the aggregate host accepted by the VM. With diagnostic, lifecycle, audio, and movie contracts
-established beneath `IHost` and the movie-mask request now neutral, move the format-independent `RgbaImage` record
-from `Sys4` to `Model` next. Update its consumers without changing the record or decoder behavior, removing the
-aggregate host's image-only dependency on the format namespace before separating larger host domains.
+established beneath `IHost` and shared movie/image transport now neutral, introduce the graphics host contract
+next. Preserve its surface, retained-range presentation, transition, texture, capture/replace, and headless-default
+behavior while leaving the remaining surface request records in place for a separate transport cleanup.
 Concrete playthrough blockers may still preempt this bounded maintenance work; the consolidation effort does
 not replace Phase B gameplay validation or the open cross-platform gates.

engine/Age.Engine.Tests/AgfDecoderTests.cs

@@ -1,4 +1,5 @@
 using System.Buffers.Binary;
+using Age.Engine.Model;
 using Age.Engine.Sys4;
 
 namespace Age.Engine.Tests;

engine/Age.Engine.Tests/CurDecoderTests.cs

@@ -1,4 +1,5 @@
 using System.Linq;
+using Age.Engine.Model;
 using Age.Engine.Sys4;
 using Xunit;
 

engine/Age.Engine.Tests/GlyphMaskCompositorTests.cs

@@ -1,5 +1,4 @@
 using Age.Engine.Model;
-using Age.Engine.Sys4;
 using Age.Engine.Text;
 
 public class GlyphMaskCompositorTests

engine/Age.Engine.Tests/MovieCorpusGateTests.cs

@@ -1,3 +1,4 @@
+using Age.Engine.Model;
 using Age.Engine.Sys4;
 
 public class MovieCorpusGateTests

engine/Age.Engine.Tests/MovieSurfaceRegistryTests.cs

@@ -1,4 +1,4 @@
-using Age.Engine.Sys4;
+using Age.Engine.Model;
 
 public class MovieSurfaceRegistryTests
 {

engine/Age.Engine/Hosting/IHost.cs

@@ -1,5 +1,4 @@
 using Age.Engine.Model;
-using Age.Engine.Sys4;
 
 namespace Age.Engine.Hosting;
 

engine/Age.Engine/Model/RgbaImage.cs

@@ -0,0 +1,4 @@
+namespace Age.Engine.Model;
+
+/// <summary>A decoded, tightly packed, top-down RGBA8 image.</summary>
+public sealed record RgbaImage(int Width, int Height, byte[] Pixels);

engine/Age.Engine/Persistence/NumberedThumbnailCodec.cs

@@ -1,5 +1,5 @@
 using System.Buffers.Binary;
-using Age.Engine.Sys4;
+using Age.Engine.Model;
 
 namespace Age.Engine.Persistence;
 

engine/Age.Engine/Sys4/AgfDecoder.cs

@@ -1,10 +1,8 @@
 using System.Buffers.Binary;
+using Age.Engine.Model;
 
 namespace Age.Engine.Sys4;
 
-/// <summary>A decoded, tightly packed, top-down RGBA8 image.</summary>
-public sealed record RgbaImage(int Width, int Height, byte[] Pixels);
-
 /// <summary>
 /// Platform-neutral Eushully AGF decoder. Format algorithm ported from GARbro's MIT-licensed
 /// ArcFormats/Eushully/ImageAGF.cs (Copyright (C) 2015 morkt).

engine/Age.Engine/Sys4/CurDecoder.cs

@@ -1,4 +1,5 @@
 using System.Buffers.Binary;
+using Age.Engine.Model;
 
 namespace Age.Engine.Sys4;
 

engine/Age.Engine/Sys4/ResourceMap.cs

@@ -1,3 +1,5 @@
+using Age.Engine.Model;
+
 namespace Age.Engine.Sys4;
 
 /// <summary>

engine/Age.Engine/Sys4/RgbaSurfaceOps.cs

@@ -1,3 +1,5 @@
+using Age.Engine.Model;
+
 namespace Age.Engine.Sys4;
 
 /// <summary>Platform-neutral mutation helpers for AGE's software-modeled RGBA surfaces.</summary>

engine/Age.Engine/Text/AgeGlyphMaskCompositor.cs

@@ -1,5 +1,4 @@
 using Age.Engine.Model;
-using Age.Engine.Sys4;
 
 namespace Age.Engine.Text;
 

engine/Age.Engine/Text/ImmediateSurfaceTextRenderer.cs

@@ -1,6 +1,5 @@
 using System.Text;
 using Age.Engine.Model;
-using Age.Engine.Sys4;
 
 namespace Age.Engine.Text;
 

engine/Age.Engine/Text/RetainedGlyphLayoutEngine.cs

@@ -1,5 +1,4 @@
 using Age.Engine.Model;
-using Age.Engine.Sys4;
 
 namespace Age.Engine.Text;
 

godot/FfmpegMovieDecoder.cs

@@ -3,6 +3,7 @@ using System.Diagnostics;
 using System.IO;
 using System.Collections.Generic;
 using System.Threading;
+using Age.Engine.Model;
 using Age.Engine.Sys4;
 
 internal interface IMoviePacingClock

godot/FfmpegMovieNative.cs

@@ -1,6 +1,7 @@
 using System;
 using System.IO;
 using System.Runtime.InteropServices;
+using Age.Engine.Model;
 using Age.Engine.Sys4;
 using Microsoft.Win32.SafeHandles;
 

godot/GodotAdvHost.AdvText.cs

@@ -4,7 +4,6 @@ using System.Linq;
 using System.Threading;
 using Age.Engine.Hosting;
 using Age.Engine.Model;
-using Age.Engine.Sys4;
 using Age.Engine.Text;
 
 public sealed partial class GodotAdvHost

godot/GpuRetainedRenderer.cs

@@ -2,7 +2,6 @@ using System;
 using System.Collections.Generic;
 using Godot;
 using Age.Engine.Model;
-using Age.Engine.Sys4;
 
 /// <summary>
 /// Godot-native presentation of AGE's sampled retained objects. Static decoded/color-key variants are

godot/IMovieDecoder.cs

@@ -1,4 +1,5 @@
 using System;
+using Age.Engine.Model;
 using Age.Engine.Sys4;
 
 internal readonly record struct MovieAudioInfo(int SampleRate, int Channels);

godot/Main.Compositor.cs

@@ -2,7 +2,6 @@ using System.Collections.Generic;
 using System.Linq;
 using Godot;
 using Age.Engine.Model;
-using Age.Engine.Sys4;
 
 public partial class Main
 {

godot/MovieSurfaceRegistry.cs

@@ -1,7 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
-using Age.Engine.Sys4;
+using Age.Engine.Model;
 
 internal readonly record struct MovieSurfaceBinding(long PlaybackId, long ResourceId, int SurfaceSlot);
 internal sealed record MovieSurfaceFrame(RgbaImage Image, string Name, int AssetId);