fix(desktop): 灯笼光晕按自身 alpha 预乘并改径向层叠，消除夜间纯白方块

- 新增 VillageArt.premultiply：MonoGame SpriteBatch 默认预乘混合，直传
  Color(r,g,b,a) 会直接加 rgb 导致多层暖色饱和成 75x75 纯白块
- lanternGlowLayers 用同心圆 pixel run 做径向衰减，逐层预乘，只在
  RiverLantern 实体处绘制
- 水面相位改 waterFrameTickAt=(tick/32+x+2y)%3，同一帧相邻砖相位不同
- 炊烟改为 drawWorld 末尾独立一遍，位置 offsetTile 0 -3，画在屋瓦/竹子之上
- 角色脚底对齐 characterFeetOffset=16 并加预乘椭圆接触阴影
- 补全 Interaction.itemName 的 ItemKind 匹配（否则非 Food 交易会崩溃且告警）

1 files changed, 3 insertions, 0 deletions

diff --git a/src/LivingVillage.Desktop/Interaction.fs b/src/LivingVillage.Desktop/Interaction.fs
index 95aa84c..b29cf6b 100644
--- a/src/LivingVillage.Desktop/Interaction.fs
+++ b/src/LivingVillage.Desktop/Interaction.fs
@@ -256,6 +256,9 @@ module M5Interaction =
     let private itemName (item: ItemKind) : string =
         match item with
         | Food -> "食物"
+        | Fish -> "鱼"
+        | Spice -> "香料"
+        | Scroll -> "卷轴"
 
     let private responseName (response: DialogueResponse) : string =
         match response with