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/shared/infrastructure/middleware/correlation-id.middleware.ts

@@ -1,5 +1,5 @@
-import { Injectable, type NestMiddleware } from '@nestjs/common';
 import { randomUUID } from 'node:crypto';
+import { Injectable, type NestMiddleware } from '@nestjs/common';
 import type { NextFunction, Request, Response } from 'express';
 
 const CORRELATION_ID_HEADER = 'x-correlation-id';

apps/api/src/modules/shared/infrastructure/middleware/csrf.middleware.ts

@@ -1,5 +1,5 @@
-import { ForbiddenException, Injectable, type NestMiddleware } from '@nestjs/common';
 import { randomBytes } from 'node:crypto';
+import { ForbiddenException, Injectable, type NestMiddleware } from '@nestjs/common';
 import type { NextFunction, Request, Response } from 'express';
 
 const CSRF_COOKIE = 'XSRF-TOKEN';

apps/api/src/modules/shared/infrastructure/middleware/request-logging.middleware.ts

@@ -1,6 +1,6 @@
 import { Injectable, type NestMiddleware } from '@nestjs/common';
 import type { NextFunction, Request, Response } from 'express';
-import { LoggerService } from '../logger.service';
+import { type LoggerService } from '../logger.service';
 
 @Injectable()
 export class RequestLoggingMiddleware implements NestMiddleware {