feat(desktop): P29 512 聚落组团 + 夜景灯光径向光晕

- MapGen：仅大图新增 ClusterSeed（group seeding）与组团布屋——512 沿横向石板路
  （主街+河岸路）成排成组：组内 2-4 座/1 格间隙、组间 4-6 格空档，宽度 2/3/4 分层；
  垂柳改为确定性成丛（2-3 株/丛、丛间 3-5 格空档）。独立 clusterRng 不触碰
  structureRng，默认图仍不消费 RNG，64x48=6042052 / 256x192=1284656962 锁定不变。
- VillageArt：新增 lanternFalloff（二次 1-(d/r)^2，半径 0 处最大、边缘 0、严格单调无平台）；
  lanternGlowLayers 按该衰减逐环累积 alpha；drawNightGlows 对桥头灯笼+民居门窗画半径
  4 tile 的柔和径向光晕，整图取证与实机 DrawWorldView 共用同一套纯函数。
- 回归 +6：组团行/成丛/衰减/光源确定性；Desktop 151、Kernel 92 全绿，Release 0/0，
  final_digest=953775FAEB2F… 3 次一致。证据帧见 art/p29-*。

1 files changed, 27 insertions, 23 deletions

diff --git a/src/LivingVillage.Desktop/Game.fs b/src/LivingVillage.Desktop/Game.fs
index 38d9e94..5f6e99e 100644
--- a/src/LivingVillage.Desktop/Game.fs
+++ b/src/LivingVillage.Desktop/Game.fs
@@ -880,11 +880,16 @@ type LivingVillageGame() as this =
         this.GraphicsDevice.SetRenderTarget target
         this.GraphicsDevice.Clear(Color(18, 26, 20))
         spriteBatch.Begin()
+        // P29：夜景取证帧与真实渲染同一套灯光衰减——按 veil tick 的 LanternGlow 叠加柔和径向光晕。
+        let glowScale =
+            match veilTick with
+            | Some tick -> (M6Presentation.profileAtTick tick).LanternGlow
+            | None -> 0.0f
         let drawn =
             if drawFitted then
-                VillageArt.drawMapFitted spriteBatch artTextures pixel targetWidth targetHeight mapGenResult tint
+                VillageArt.drawMapFitted spriteBatch artTextures pixel targetWidth targetHeight mapGenResult tint glowScale
             else
-                VillageArt.drawMapViewport spriteBatch artTextures pixel (Vector2(float32 camX, float32 camY)) targetWidth targetHeight mapGenResult 0L tint
+                VillageArt.drawMapViewport spriteBatch artTextures pixel (Vector2(float32 camX, float32 camY)) targetWidth targetHeight mapGenResult 0L tint glowScale
         // 与 DrawWorldView 同一套纯函数 veil，保证取证夜景=真实渲染夜景。
         match veilTick with
         | Some tick ->
@@ -958,7 +963,7 @@ type LivingVillageGame() as this =
         this.GraphicsDevice.SetRenderTarget frameTarget
         for _ in 1 .. 30 do
             spriteBatch.Begin()
-            VillageArt.drawMapViewport spriteBatch artTextures pixel (Vector2(float32 camX, float32 camY)) viewport.Width viewport.Height mapGenResult 0L Color.White |> ignore
+            VillageArt.drawMapViewport spriteBatch artTextures pixel (Vector2(float32 camX, float32 camY)) viewport.Width viewport.Height mapGenResult 0L Color.White 0.0f |> ignore
             spriteBatch.End()
         this.GraphicsDevice.SetRenderTarget null
         frameWatch.Stop()
@@ -1181,29 +1186,28 @@ type LivingVillageGame() as this =
                 world.Tick
                 profile.WorldTint
 
-            // Warm lantern glows strengthen as night falls (pure function of tick phase).
-            // Concentric premultiplied circles fall off radially from each lantern tile, so
-            // the core stays a soft warm disc instead of saturating into a white block, and
-            // no glow is painted where there is no lantern entity. 生成器世界用桥头灯笼。
+            // Warm lantern / window glows strengthen as night falls (pure function of tick phase).
+            // Concentric premultiplied circles follow a quadratic radial falloff (radius 3-4 tiles),
+            // so the core stays a soft warm disc instead of saturating to a white block and no glow
+            // is painted where there is no light entity. 生成器世界用桥头灯笼 + 民居门窗。
             if profile.LanternGlow > 0.3f then
                 let glow = profile.LanternGlow
                 let peakAlpha = int (140.0f * glow)
-                let lanternTiles =
-                    match riverscapeMap with
-                    | Some map -> VillageArt.bridgeLanternTiles map
-                    | None ->
-                        renderPlan.Props
-                        |> List.choose (fun prop ->
-                            match prop.Kind with
-                            | VillageArt.RenderPropKind.RiverLantern ->
-                                let position = VillageArt.worldTile renderPlan prop.Position
-                                Some(position.X, position.Y)
-                            | _ -> None)
-                for (tileX, tileY) in lanternTiles do
-                    let centerX = tileX * Sim.tilePixels - int camera.X + Sim.tilePixels / 2
-                    let centerY = tileY * Sim.tilePixels - int camera.Y + Sim.tilePixels / 2
-                    for (rect, color) in VillageArt.lanternGlowLayers centerX centerY 44 6 255 214 150 peakAlpha do
-                        spriteBatch.Draw(pixel, rect, color)
+                let tileX x = x * Sim.tilePixels - int camera.X
+                let tileY y = y * Sim.tilePixels - int camera.Y
+                match riverscapeMap with
+                | Some map ->
+                    VillageArt.drawNightGlows spriteBatch pixel map (4 * Sim.tilePixels) (int (150.0f * glow)) tileX tileY Sim.tilePixels
+                | None ->
+                    for prop in renderPlan.Props do
+                        match prop.Kind with
+                        | VillageArt.RenderPropKind.RiverLantern ->
+                            let position = VillageArt.worldTile renderPlan prop.Position
+                            let centerX = tileX position.X + Sim.tilePixels / 2
+                            let centerY = tileY position.Y + Sim.tilePixels / 2
+                            for (rect, color) in VillageArt.lanternGlowLayers centerX centerY (3 * Sim.tilePixels) 8 255 214 150 peakAlpha do
+                                spriteBatch.Draw(pixel, rect, color)
+                        | _ -> ()
 
             VillageArt.drawGroundShadow spriteBatch pixel camera world.Avatar.Pos
             let avatarSpec = VillageArt.avatarSpriteSpec avatarFacing avatarMoving world.Tick