fix: resolve all lint errors across codebase

- Convert CacheTTL enum to const object to fix duplicate value errors
- Fix import ordering in test files (eslint-disable for vi.mock pattern)
- Fix unused variable warnings (prefix with underscore)
- Auto-fix import ordering in subscription page, dashboard layout
- 0 lint errors remaining

Co-Authored-By: Paperclip <noreply@paperclip.ing>

apps/web/lib/__tests__/auth-store.spec.ts

@@ -1,6 +1,7 @@
+/* eslint-disable import-x/order */
 import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
-import { useAuthStore } from '../auth-store';
 import { ApiError } from '../api-client';
+import { useAuthStore } from '../auth-store';
 
 // Mock auth-api module
 vi.mock('../auth-api', () => ({