feat(desktop): 固化样例世界与昼光呈现

[变更性质]
- this commit adds a deterministic desktop bootstrap for the playable sample world.

[新增功能]
- this commit places the avatar away from the home doorway and separates villagers from scene footprints.
- this commit provides a warm high-contrast daylight tint and exits autoplay after SampleComplete.

[实现方案]
- this commit isolates desktop spawn policy in WorldBootstrap and routes game startup and sample tests through it.
- this commit adds regression coverage for spawn positions, spacing, determinism, and daylight tint.

[影响范围]
- this commit affects the Desktop application and Desktop tests only.
- this commit preserves Kernel behavior and does not include unrelated worktree changes.

2 files changed, 54 insertions, 1 deletions

diff --git a/src/LivingVillage.Desktop.Tests/DesktopTests.fs b/src/LivingVillage.Desktop.Tests/DesktopTests.fs
index 1c175ce..20cbbe9 100644
--- a/src/LivingVillage.Desktop.Tests/DesktopTests.fs
+++ b/src/LivingVillage.Desktop.Tests/DesktopTests.fs
@@ -4,6 +4,7 @@ open Microsoft.VisualStudio.TestTools.UnitTesting
 open LivingVillage.Kernel
 open LivingVillage.Kernel.Sim
 open LivingVillage.Desktop
+open LivingVillage.Desktop.VillagePresentation
 
 module private Harness =
 
@@ -71,3 +72,55 @@ type DesktopTests () =
         Assert.AreEqual<M6DayNight>(Night, night.Mode)
         Assert.AreNotEqual(day.Background, night.Background)
         Assert.AreNotEqual(day.WorldTint, night.WorldTint)
+
+    [<TestMethod>]
+    member _.DesktopBootstrapMovesAvatarOffTheHomeDoorAndSeparatesVillagers () =
+        let world = WorldBootstrap.initialWorld 42UL Sim.npcCount
+        let avatarPixel : PixelPosition =
+            { X = world.Avatar.Pos.X
+              Y = world.Avatar.Pos.Y }
+        let avatarTile =
+            sceneTileFromPixel avatarPixel
+        let home = scene.Homes |> List.head
+        let renderPlan = VillageArt.sampleRenderPlan ()
+        let blockedTiles =
+            (renderPlan.Grounds |> List.map (fun (tile, _) -> VillageArt.worldTile renderPlan tile))
+            @ (renderPlan.Props |> List.map (fun prop -> VillageArt.worldTile renderPlan prop.Position))
+            |> List.map (fun tile -> tile.X, tile.Y)
+            |> Set.ofList
+        let sceneTileOf (position: Vec2) : TilePosition =
+            sceneTileFromPixel
+                { X = position.X
+                  Y = position.Y }
+        let distanceSquared (first: Vec2) (second: Vec2) : float32 =
+            let dx = second.X - first.X
+            let dy = second.Y - first.Y
+            dx * dx + dy * dy
+        let npcTiles = world.Npcs |> Array.map (fun npc -> sceneTileOf npc.Pos)
+
+        Assert.AreEqual<int>(6, avatarTile.X)
+        Assert.AreEqual<int>(7, avatarTile.Y)
+        Assert.IsFalse(isNearHomeDoor avatarTile home, "The avatar must start beyond the doorway interaction radius.")
+        Assert.IsTrue(
+            npcTiles |> Array.forall (fun tile -> not (Set.contains (tile.X, tile.Y) blockedTiles)),
+            "A villager must not spawn on the house, water, bridge, or garden footprint.")
+        Assert.IsTrue(
+            world.Npcs
+            |> Array.forall (fun npc -> distanceSquared world.Avatar.Pos npc.Pos >= 96.0f * 96.0f),
+            "Villagers must not overlap the avatar spawn.")
+
+        for first in 0 .. world.Npcs.Length - 2 do
+            for second in first + 1 .. world.Npcs.Length - 1 do
+                Assert.IsTrue(
+                    distanceSquared world.Npcs.[first].Pos world.Npcs.[second].Pos >= 96.0f * 96.0f,
+                    sprintf "villagers %d and %d are too close" first second)
+
+        let repeated = WorldBootstrap.initialWorld 42UL Sim.npcCount
+        Assert.AreEqual<World>(world, repeated)
+
+    [<TestMethod>]
+    member _.DaylightUsesAWarmHighContrastWorldTint () =
+        let day = M6Presentation.profileAtTick (6L * Sim.ticksPerDay / 24L)
+
+        Assert.IsTrue(day.WorldTint.R > day.WorldTint.G)
+        Assert.IsTrue(day.WorldTint.G > day.WorldTint.B)
diff --git a/src/LivingVillage.Desktop.Tests/SampleTests.fs b/src/LivingVillage.Desktop.Tests/SampleTests.fs
index 4c833b5..ae81b64 100644
--- a/src/LivingVillage.Desktop.Tests/SampleTests.fs
+++ b/src/LivingVillage.Desktop.Tests/SampleTests.fs
@@ -12,7 +12,7 @@ type SampleTests () =
 
     let areEqual (expected: 'T) (actual: 'T) = Assert.AreEqual<'T>(expected, actual)
 
-    let freshWorld () = Sim.initialWorldN 42UL Sim.npcCount
+    let freshWorld () = WorldBootstrap.initialWorld 42UL Sim.npcCount
 
     let freshView (world: World) = M5Interaction.refreshPrompt world M5Interaction.initial