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.

1 files changed, 36 insertions, 0 deletions

diff --git a/src/LivingVillage.Desktop/WorldBootstrap.fs b/src/LivingVillage.Desktop/WorldBootstrap.fs
new file mode 100644
index 0000000..612931b
--- /dev/null
+++ b/src/LivingVillage.Desktop/WorldBootstrap.fs
@@ -0,0 +1,36 @@
+namespace LivingVillage.Desktop
+
+open LivingVillage.Kernel
+open LivingVillage.Kernel.Sim
+
+module WorldBootstrap =
+
+    let private tileCenter (x: int) (y: int) : Vec2 =
+        { X = float32 (x * Sim.tilePixels + Sim.tilePixels / 2)
+          Y = float32 (y * Sim.tilePixels + Sim.tilePixels / 2) }
+
+    let private npcSpawnTiles : (int * int) array =
+        [| for y in [ 14; 18; 28; 32; 36; 40 ] do
+               for x in [ 24; 28; 32; 36; 40 ] do
+                   yield x, y |]
+
+    let private avatarSpawnPosition = tileCenter 31 25
+
+    let initialWorld (seed: uint64) (count: int) : World =
+        if count < 0 || count > npcSpawnTiles.Length then
+            invalidArg (nameof count) "Desktop bootstrap supports at most 30 NPCs."
+
+        let baseWorld = Sim.initialWorldN seed count
+        let avatar =
+            { baseWorld.Avatar with
+                Pos = avatarSpawnPosition
+                Mind = { baseWorld.Avatar.Mind with Target = avatarSpawnPosition } }
+        let npcs =
+            baseWorld.Npcs
+            |> Array.mapi (fun index npc ->
+                let x, y = npcSpawnTiles.[index]
+                { npc with Pos = tileCenter x y })
+
+        { baseWorld with
+            Avatar = avatar
+            Npcs = npcs }