fix(graphics): tune presets, single-line ui, vegetation LOD by nearest instance

- Bump high to 30m chunk / HD<20m and ultra to HD<30m so HD models
  persist further before swapping.
- Render the 5 graphics preset cards on a single row.
- Vegetation LOD selection now uses the distance to the nearest instance
  in each chunk instead of the chunk centre, matching MapInstancingSystem
  and avoiding premature LOD swaps when the camera enters a chunk.

src/data/world/graphicsConfig.ts

@@ -39,12 +39,12 @@ export const GRAPHICS_PRESETS = {
   },
   high: {
     label: "High",
-    chunkLoadRadius: 35,
-    chunkUnloadRadius: 45,
+    chunkLoadRadius: 30,
+    chunkUnloadRadius: 40,
     chunkStreamingEnabled: true,
     fogEnabled: false,
     forceLodModels: false,
-    lodHighDetailDistance: 10,
+    lodHighDetailDistance: 20,
   },
   ultra: {
     label: "Ultra",
@@ -53,7 +53,7 @@ export const GRAPHICS_PRESETS = {
     chunkStreamingEnabled: true,
     fogEnabled: false,
     forceLodModels: false,
-    lodHighDetailDistance: 20,
+    lodHighDetailDistance: 30,
   },
   max: {
     label: "Max",

src/index.css

@@ -1544,7 +1544,7 @@ canvas {
 }
 
 .game-settings-menu__choice-group--presets {
-  grid-template-columns: repeat(4, minmax(0, 1fr));
+  grid-template-columns: repeat(5, minmax(0, 1fr));
 }
 
 .game-settings-menu__choice-group button,

src/world/vegetation/VegetationSystem.tsx

@@ -109,12 +109,17 @@ function useVegetationChunkModelPaths(
     const next = new Map<string, string>();
 
     for (const chunk of chunks) {
+      let nearestDistance = Number.POSITIVE_INFINITY;
+      for (const instance of chunk.instances) {
         const distance = Math.hypot(
-        chunk.centerX - cameraX,
-        chunk.centerZ - cameraZ,
+          instance.position[0] - cameraX,
+          instance.position[2] - cameraZ,
         );
+        if (distance < nearestDistance) nearestDistance = distance;
+      }
+
       const modelPath = selectMapModelPathByDistance({
-        distance,
+        distance: nearestDistance,
         modelName: VEGETATION_TYPES[chunk.type].mapName,
         modelPath: chunk.modelPath,
         preset,