perf(map): reuse resources across routes

Preserve standard network layers between map pages while disposing route-owned overlays and controls to prevent memory growth.

src/utils/layers.ts

@@ -70,6 +70,12 @@ export class DeckLayer extends Layer {
     this.deck.setProps({ layers });
   }
 
+  resetSessionLayers(): void {
+    if (this.isDisposed) return;
+    this.userVisibility.clear();
+    this.deck.setProps({ layers: [] });
+  }
+
   // 获取当前图层
   getDeckLayers(): any[] {
     if (this.isDisposed) return [];