feat(desktop): add Chinese village presentation prototype

[Change Nature]
- This commit adds a deterministic presentation-model feature, not MonoGame rendering.

[New Capability]
- Provide an immutable Jiangnan village scene with homes, waterways, paths, bridge, bamboo, and garden elements.
- Provide typed home transitions, four-way input mapping, tick animation, NPC styles, and Chinese stage-one labels.

[Implementation]
- Add the pure VillagePresentation module and six focused MSTest cases.
- Keep the model free of mutable global state and update only the required F# compile order.

[Impact]
- This commit affects the Desktop presentation and test projects only.
- Kernel behavior, Game.fs wiring, MonoGame drawing, and existing acceptance artifacts remain unchanged.

2 files changed, 103 insertions, 0 deletions

diff --git a/src/LivingVillage.Desktop.Tests/LivingVillage.Desktop.Tests.fsproj b/src/LivingVillage.Desktop.Tests/LivingVillage.Desktop.Tests.fsproj
index 405e8b5..569190a 100644
--- a/src/LivingVillage.Desktop.Tests/LivingVillage.Desktop.Tests.fsproj
+++ b/src/LivingVillage.Desktop.Tests/LivingVillage.Desktop.Tests.fsproj
@@ -9,6 +9,7 @@
     <Compile Include="DesktopTests.fs" />
     <Compile Include="M6aTests.fs" />
     <Compile Include="M6bTests.fs" />
+    <Compile Include="PrototypeTests.fs" />
   </ItemGroup>
 
   <ItemGroup>
diff --git a/src/LivingVillage.Desktop.Tests/PrototypeTests.fs b/src/LivingVillage.Desktop.Tests/PrototypeTests.fs
new file mode 100644
index 0000000..b959d70
--- /dev/null
+++ b/src/LivingVillage.Desktop.Tests/PrototypeTests.fs
@@ -0,0 +1,102 @@
+namespace LivingVillage.Desktop.Tests
+
+open Microsoft.VisualStudio.TestTools.UnitTesting
+open LivingVillage.Kernel.Sim
+open LivingVillage.Desktop.VillagePresentation
+
+[<TestClass>]
+type PrototypeTests () =
+
+    [<TestMethod>]
+    member _.SceneContainsTheJiangnanPrototypeAndReachableHomeDoor () =
+        let first = createScene ()
+        let second = createScene ()
+        let requiredProps =
+            [ WhiteWallDarkTileHome
+              HomeDoor
+              RiverChannel
+              RiverBank
+              StoneBridge
+              StonePaving
+              Bamboo
+              VegetableGarden ]
+
+        Assert.AreEqual<PrototypeScene>(first, second)
+        Assert.AreEqual<PrototypeScene>(scene, first)
+        Assert.IsTrue(first.Homes.Length > 0, "The prototype needs at least one home.")
+        Assert.IsTrue(
+            requiredProps
+            |> List.forall (fun prop -> first.Elements |> List.exists (fun element -> element.Prop = prop)),
+            "The scene is missing one or more required Jiangnan elements.")
+
+        let home = first.Homes |> List.head
+        Assert.IsTrue(isNearHomeDoor first.InitialPlayerPosition home)
+
+    [<TestMethod>]
+    member _.HomeEntryAndExitExposeExplicitSuccessAndFailureBranches () =
+        let scene = createScene ()
+        let home = scene.Homes |> List.head
+        let entered = enterHome scene.InitialPlayerPosition Outside
+
+        match entered with
+        | Ok (Inside enteredHome) ->
+            Assert.AreEqual<HomeId>(home.Id, enteredHome)
+        | Ok Outside -> Assert.Fail("Entering a home must produce Inside state.")
+        | Error failure -> Assert.Fail(sprintf "Expected entry to succeed, got %A." failure)
+
+        match entered with
+        | Ok inside ->
+            match enterHome scene.InitialPlayerPosition inside with
+            | Error (AlreadyInsideHome homeId) -> Assert.AreEqual<HomeId>(home.Id, homeId)
+            | other -> Assert.Fail(sprintf "Expected AlreadyInsideHome, got %A." other)
+        | Error _ -> Assert.Fail("The first entry must succeed before checking the duplicate entry.")
+
+        match exitHome (Inside home.Id) with
+        | Ok Outside -> ()
+        | other -> Assert.Fail(sprintf "Expected exit to succeed, got %A." other)
+
+        match exitHome Outside with
+        | Error NotInsideHome -> ()
+        | other -> Assert.Fail(sprintf "Expected NotInsideHome, got %A." other)
+
+        match exitHome (Inside(HomeId 999)) with
+        | Error(HomeNotFound(HomeId 999)) -> ()
+        | other -> Assert.Fail(sprintf "Expected HomeNotFound, got %A." other)
+
+        let farAway = { X = scene.InitialPlayerPosition.X + 20; Y = scene.InitialPlayerPosition.Y + 20 }
+        match enterHome farAway Outside with
+        | Error NotNearHomeDoor -> ()
+        | other -> Assert.Fail(sprintf "Expected NotNearHomeDoor, got %A." other)
+
+    [<TestMethod>]
+    member _.FourWayInputMapsToFourDirections () =
+        Assert.AreEqual<Direction option>(Some North, directionForInput UpInput)
+        Assert.AreEqual<Direction option>(Some South, directionForInput DownInput)
+        Assert.AreEqual<Direction option>(Some West, directionForInput LeftInput)
+        Assert.AreEqual<Direction option>(Some East, directionForInput RightInput)
+        Assert.AreEqual<Direction option>(None, directionForInput NoInput)
+
+    [<TestMethod>]
+    member _.AnimationFrameChangesWithSimulationTick () =
+        let first = animationFrame (SimulationTick 0L)
+        let second = animationFrame (SimulationTick 4L)
+        let nextCycle = animationFrame (SimulationTick 8L)
+
+        Assert.AreNotEqual<CharacterAnimationFrame>(first, second)
+        Assert.AreEqual<CharacterAnimationFrame>(first, nextCycle)
+
+    [<TestMethod>]
+    member _.NpcIdProducesStableAndDistinctCharacterStyles () =
+        let first = characterStyle (NpcId 0)
+        let sameNpc = characterStyle (NpcId 0)
+        let second = characterStyle (NpcId 1)
+
+        Assert.AreEqual<CharacterStyle>(first, sameNpc)
+        Assert.AreNotEqual<CharacterStyle>(first, second)
+
+    [<TestMethod>]
+    member _.StageOneCopyProvidesChineseInteractionLabels () =
+        Assert.AreEqual<string>("互动", stageOneCopy.Interact)
+        Assert.AreEqual<string>("需求", stageOneCopy.Needs)
+        Assert.AreEqual<string>("交易", stageOneCopy.Trade)
+        Assert.AreEqual<string>("进入民居", stageOneCopy.EnterHome)