fix: eliminate untyped repository returns and standardize DomainException usage across all handlers

- Create typed DTOs (ListingDetailData, ListingSearchItem, ListingSellerItem) for repository read methods
- Replace all Promise<any> and PaginatedResult<any> with concrete types in repository interface and implementation
- Remove `as any` casts in search params by using Prisma enum types (TransactionType, PropertyType)
- Migrate all 16 handlers from NestJS built-in exceptions to domain exceptions (NotFoundException, ValidationException, etc.)
- Add CONTRIBUTING.md documenting error handling convention
- All 230 tests pass, typecheck clean

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

apps/api/src/modules/auth/application/queries/get-profile/get-profile.handler.ts

@@ -1,5 +1,6 @@
 import { type IQueryHandler, QueryHandler } from '@nestjs/cqrs';
-import { Inject, NotFoundException } from '@nestjs/common';
+import { Inject } from '@nestjs/common';
+import { NotFoundException } from '@modules/shared/domain/domain-exception';
 import { CacheService, CachePrefix, CacheTTL } from '@modules/shared/infrastructure/cache.service';
 import { GetProfileQuery } from './get-profile.query';
 import { USER_REPOSITORY, type IUserRepository } from '../../../domain/repositories/user.repository';
@@ -31,7 +32,7 @@ export class GetProfileHandler implements IQueryHandler<GetProfileQuery> {
       async () => {
         const user = await this.userRepo.findById(query.userId);
         if (!user) {
-          throw new NotFoundException('Người dùng không tồn tại');
+          throw new NotFoundException('Người dùng', query.userId);
         }
 
         return {