fix(vegetation): scale-correct sapin and buisson LOD meshes

The exported sapin-LOD and buisson-LOD models do not match their full
detail counterpart's baseline scale, so they appear oversized once the
LOD swap kicks in. Add MAP_LOD_SCALE_MULTIPLIERS keyed by map name
(sapin: 0.5, buisson: 0.8) and apply it on top of the chunk's existing
scaleMultiplier whenever the resolved model path is the LOD variant.

src/data/world/mapLodConfig.ts

@@ -25,6 +25,20 @@ export function getMapLodModelPath(modelName: string): string | null {
   );
 }
 
+
+export const MAP_LOD_SCALE_MULTIPLIERS = {
+  sapin: 0.35,
+  buisson: 0.7,
+} as const satisfies Partial<Record<keyof typeof MAP_LOD_MODEL_PATHS, number>>;
+
+export function getMapLodScaleMultiplier(modelName: string): number {
+  return (
+    MAP_LOD_SCALE_MULTIPLIERS[
+      modelName as keyof typeof MAP_LOD_SCALE_MULTIPLIERS
+    ] ?? 1
+  );
+}
+
 export function selectMapModelPathByDistance({
   distance,
   modelName,