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/web/components/listings/listing-form-steps.tsx

@@ -1,15 +1,15 @@
 'use client';
 
+import type { UseFormRegister, FieldErrors } from 'react-hook-form';
 import { Input } from '@/components/ui/input';
 import { Label } from '@/components/ui/label';
-import { Textarea } from '@/components/ui/textarea';
 import { Select } from '@/components/ui/select';
+import { Textarea } from '@/components/ui/textarea';
 import {
   TRANSACTION_TYPES,
   PROPERTY_TYPES,
   DIRECTIONS,
 } from '@/lib/validations/listings';
-import type { UseFormRegister, FieldErrors } from 'react-hook-form';
 import type { CreateListingFormData } from '@/lib/validations/listings';
 
 interface StepProps {