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/api/src/modules/metrics/presentation/interceptors/__tests__/http-metrics.interceptor.spec.ts

@@ -1,6 +1,6 @@
 import { type CallHandler, type ExecutionContext } from '@nestjs/common';
 import { of, throwError } from 'rxjs';
-import { MetricsService } from '../../../infrastructure/metrics.service';
+import { type MetricsService } from '../../../infrastructure/metrics.service';
 import { HttpMetricsInterceptor } from '../http-metrics.interceptor';
 
 describe('HttpMetricsInterceptor', () => {