fix: production readiness — resolve build, lint, and code quality issues

- Fix Next.js build failure: remove duplicate route at (dashboard)/listings/[id]
  that conflicted with (public)/listings/[id] (same URL path in two route groups)
- Fix 772 ESLint errors: auto-fix import ordering (import-x/order), remove unused
  imports/variables, convert empty interfaces to type aliases, replace require()
  with ESM imports, fix consistent-type-imports violations
- Add CLAUDE.md for developer onboarding documentation
- All checks pass: 0 lint errors, typecheck clean, 230 tests passing, build success

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

apps/api/src/modules/auth/__tests__/auth.integration.spec.ts

@@ -1,11 +1,11 @@
-import { describe, it, expect, beforeAll, afterAll } from 'vitest';
-import { Test, type TestingModule } from '@nestjs/testing';
 import { type INestApplication, ValidationPipe } from '@nestjs/common';
 import { CqrsModule } from '@nestjs/cqrs';
+import { Test, type TestingModule } from '@nestjs/testing';
 import request from 'supertest';
-import { AuthModule } from '../auth.module';
+import { describe, it, expect, beforeAll, afterAll } from 'vitest';
 import { PrismaService } from '@modules/shared/infrastructure/prisma.service';
 import { SharedModule } from '@modules/shared/shared.module';
+import { AuthModule } from '../auth.module';
 
 describe('Auth Controller (Integration)', () => {
   let app: INestApplication;