Move movie transition request to model

docs/PROJECT-STRUCTURE.md

@@ -167,7 +167,8 @@ timed-deadline waiting, frame yield, and scene reset. `engine/Age.Engine/Hosting
 SFX, fade, volume, and route-control contracts, including the compatibility overload/default chains used by
 simple hosts. `engine/Age.Engine/Hosting/IMovieHost.cs` owns ordinary, positioned, mask-transition, activity-query,
 and modal movie playback contracts. `IHost` inherits all four focused contracts; their required and default
-behavior is unchanged, and movie/graphics transport records remain in their existing locations for now.
+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/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

@@ -776,6 +776,11 @@ do not mix mechanical moves with semantic changes.
    `MovieMaskTransitionRequest` remain in their prior locations pending a separate dependency-cleanup slice.
    Runtime validation remains green.
 
+   The fourth bounded contract slice moved the unchanged `MovieMaskTransitionRequest` record from `Hosting` to
+   `Model`. VM, Godot, tests, and the movie host contract already consumed `Model`, so no call sites changed;
+   removing the two now-unused imports eliminates `GfxState`'s reverse dependency on the host namespace. 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
@@ -1136,8 +1141,8 @@ 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`, move the neutral `MovieMaskTransitionRequest` contract from `Hosting` to `Model` next
+established beneath `IHost` and the movie-mask request now neutral, move the format-independent `RgbaImage` record
-to remove `GfxState`'s reverse dependency on the host namespace, preserving the record's public shape and every
+from `Sys4` to `Model` next. Update its consumers without changing the record or decoder behavior, removing the
-consumer before separating larger host domains.
+aggregate host's image-only dependency on the format namespace before separating larger host domains.
 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/Hosting/IHost.cs

@@ -28,13 +28,6 @@ public readonly record struct SurfaceRectCopy(
     int SourceSurface, int DestinationSurface, int SourceX, int SourceY,
     int Width, int Height, int DestinationX, int DestinationY);
 
-/// <summary>Opcode 0x24d's captured-range movie-mask transition. The movie's decoded green channel
-/// becomes a byte-per-pixel alpha mask over SourceRange in the scratch surface.</summary>
-public readonly record struct MovieMaskTransitionRequest(
-    long CommandKey, int SurfaceSlot, long SourceRangeStart, int SourceRangeCount,
-    int X, int Y, int Width, int Height, long Mode, long ResourceId,
-    long StartDelayMs, long DurationMs);
-
 /// <summary>A synchronous AGE-owned diagnostic prompt after native body/context formatting.</summary>
 public readonly record struct DiagnosticMessage(string Caption, string Text);
 

engine/Age.Engine/Model/GfxState.Contracts.cs

@@ -1,5 +1,3 @@
-using Age.Engine.Hosting;
-
 namespace Age.Engine.Model;
 
 /// <summary>The sampled native one-shot channels carried to the compositor: op 0x21e scale, op 0x21f

engine/Age.Engine/Model/GfxState.Presentation.cs

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

engine/Age.Engine/Model/MovieMaskTransitionRequest.cs

@@ -0,0 +1,8 @@
+namespace Age.Engine.Model;
+
+/// <summary>Opcode 0x24d's captured-range movie-mask transition. The movie's decoded green channel
+/// becomes a byte-per-pixel alpha mask over SourceRange in the scratch surface.</summary>
+public readonly record struct MovieMaskTransitionRequest(
+    long CommandKey, int SurfaceSlot, long SourceRangeStart, int SourceRangeCount,
+    int X, int Y, int Width, int Height, long Mode, long ResourceId,
+    long StartDelayMs, long DurationMs);