Fix code scanning alert no. 81: Prototype-polluting assignment

Co-authored-by: Copilot Autofix powered by AI <62310815+github-advanced-security[bot]@users.noreply.github.com>

Author: ntucker

packages/core/src/state/GCPolicy.ts

@@ -5,7 +5,7 @@ import Controller from '../controller/Controller.js';
 
 export class GCPolicy implements GCInterface {
   protected endpointCount: Record<string, number> = {};
-  protected entityCount: Record<string, Record<string, number>> = {};
+  protected entityCount: Map<string, Map<string, number>> = new Map();
   protected endpoints = new Set<string>();
   protected entities: EntityPath[] = [];
   declare protected intervalId: ReturnType<typeof setInterval>;
@@ -41,9 +41,9 @@ export class GCPolicy implements GCInterface {
       this.endpointCount[key]++;
       paths.forEach(path => {
         if (!(path.key in this.endpointCount)) {
-          this.entityCount[path.key] = {};
+          this.entityCount.set(path.key, new Map());
         }
-        this.entityCount[path.key][path.pk]++;
+        this.entityCount.get(path.key)!.set(path.pk, (this.entityCount.get(path.key)!.get(path.pk) || 0) + 1);
       });
 
       // decrement
@@ -57,7 +57,7 @@ export class GCPolicy implements GCInterface {
           if (!(path.key in this.endpointCount)) {
             return;
           }
-          this.entityCount[path.key][path.pk]--;
+          this.entityCount.get(path.key)!.set(path.pk, this.entityCount.get(path.key)!.get(path.pk)! - 1);
         });
       };
     };