Implement friends balance retrieval and enhance HomeScreen actions (#114)

* feat: Implement friends balance retrieval and display in FriendsScreen; enhance balance calculation logic

* feat: Update HomeScreen header to include group creation and joining actions; remove redundant buttons

* Remove package.json from frontend directory to clean up unused dependencies

* 📝 CodeRabbit Chat: Add comprehensive Jest unit tests for API, utils, and screen components

* Revert "📝 CodeRabbit Chat: Add comprehensive Jest unit tests for API, utils, and screen components"

This reverts commit df45073.

---------

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>
Co-authored-by: patel.devasy.23 <[email protected]>

Author: 3 people

frontend/api/groups.js

@@ -82,3 +82,11 @@ export const getUserBalanceSummary = (token) => {
     },
   });
 };
+
+export const getFriendsBalance = (token) => {
+  return apiClient.get('/users/me/friends-balance', {
+    headers: {
+      Authorization: `Bearer ${token}`,
+    },
+  });
+};