refactor: make match-collector export its types, and consume them in frontend

frontend/utils/buildHelpers.ts

@@ -1,3 +1,5 @@
+import type { Build, ItemTree } from 'match_collector'
+
 /**
  * Gets all late game items from the item tree (items beyond first level)
  * Returns a flat array of unique items with their counts
@@ -55,7 +57,9 @@ function trimTreeDepth(tree: ItemTree, maxDepth: number, currentDepth: number =
     count: tree.count,
     data: tree.data,
     children: [],
-    tags: tree.tags
+    tags: tree.tags,
+    boughtWhen: tree.boughtWhen,
+    platformCount: tree.platformCount
   }
 
   // If we haven't reached maxDepth, include children