feat(ci): add Codecov integration with frontend Jest coverage and CODECOV_TOKEN

Agent-Logs-Url: https://github.com/christianlouis/InboxConverge/sessions/53f8deb9-5c3a-4940-a058-c8ee7e4104e0

Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>

frontend/src/store/authStore.test.ts

@@ -1,5 +1,3 @@
-import { describe, it, expect, beforeEach } from 'bun:test';
-
 // Mock localStorage
 const localStorageMock = (() => {
   let store: Record<string, string> = {};