reworked developer tools with diagnostics, storage viewers and release-capable debug overlays

lib/api/cache_store.dart

@@ -5,6 +5,8 @@ import 'dart:io';
 import 'package:flutter/foundation.dart';
 import 'package:path_provider/path_provider.dart';
 
+import '../utils/directory_size.dart';
+
 /// One cached response: the raw JSON payload and when it was stored.
 class CacheEntry {
   final String json;
@@ -140,18 +142,7 @@ class CacheStore {
   }
 
   /// Total size of all entries in bytes.
-  Future<int> totalSize() async {
-    try {
-      final dir = await _directory();
-      var sum = 0;
-      await for (final entity in dir.list()) {
-        if (entity is File) sum += await entity.length();
-      }
-      return sum;
-    } on Object {
-      return 0;
-    }
-  }
+  Future<int> totalSize() async => directorySize(await _directory());
 
   /// Parses the stored file format; public for tests.
   static CacheEntry? parse(String raw) {