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/app/auth/callback/google/page.tsx

@@ -1,8 +1,8 @@
 'use client';
 
-import { useEffect, useRef } from 'react';
-import { useRouter, useSearchParams } from 'next/navigation';
 import { Loader2 } from 'lucide-react';
+import { useRouter, useSearchParams } from 'next/navigation';
+import { useEffect, useRef } from 'react';
 import { useAuthStore } from '@/lib/auth-store';
 
 export default function GoogleCallbackPage() {

apps/web/app/auth/callback/zalo/page.tsx

@@ -1,8 +1,8 @@
 'use client';
 
-import { useEffect, useRef } from 'react';
-import { useRouter, useSearchParams } from 'next/navigation';
 import { Loader2 } from 'lucide-react';
+import { useRouter, useSearchParams } from 'next/navigation';
+import { useEffect, useRef } from 'react';
 import { useAuthStore } from '@/lib/auth-store';
 
 export default function ZaloCallbackPage() {