구현: W2 도메인·인프라·서비스 레이어

Domain 레이어:
- Enums: InquiryStatus (New/Contacted/Contracted/Closed)
- Enums: ServiceType (기장/종소세/부가세/양도세/증여상속/기타)
- Entities: Category, BlogPost, Inquiry, AdminUser (DB 매핑)
- Interfaces: IBlogPostRepository, ICategoryRepository, IInquiryRepository, IDbConnectionFactory

Infrastructure 레이어:
- DbConnectionFactory: PostgreSQL 연결 팩토리 (Npgsql)
- BlogPostRepository: GetBySlug, GetPublishedPaged, Create, Update, Delete, IncrementViewCount
- CategoryRepository: GetAll, GetBySlug
- InquiryRepository: Create, GetPaged, UpdateStatus
- NuGet 의존성: Dapper 2.1.15, Npgsql 8.0.1, Configuration, DependencyInjection
- DependencyInjection: AddInfrastructure() 확장 메서드

기술 결정:
- Dapper로 SQL 완전 제어
- PostgreSQL 다중 쿼리 (QueryMultiple) 페이징 최적화
- 한국어 파라미터 처리 (::int, ::text 타입 명시)

Co-Authored-By: Claude <noreply@anthropic.com>

TaxBaik.Domain/Interfaces/IBlogPostRepository.cs

@@ -0,0 +1,16 @@
+namespace TaxBaik.Domain.Interfaces;
+
+using TaxBaik.Domain.Entities;
+
+public interface IBlogPostRepository
+{
+    Task<BlogPost?> GetByIdAsync(int id, CancellationToken cancellationToken = default);
+    Task<BlogPost?> GetBySlugAsync(string slug, CancellationToken cancellationToken = default);
+    Task<(IEnumerable<BlogPost> Items, int Total)> GetPublishedPagedAsync(
+        int page, int pageSize, int? categoryId = null, CancellationToken cancellationToken = default);
+    Task<IEnumerable<BlogPost>> GetAllForAdminAsync(CancellationToken cancellationToken = default);
+    Task<int> CreateAsync(BlogPost post, CancellationToken cancellationToken = default);
+    Task UpdateAsync(BlogPost post, CancellationToken cancellationToken = default);
+    Task DeleteAsync(int id, CancellationToken cancellationToken = default);
+    Task IncrementViewCountAsync(int id, CancellationToken cancellationToken = default);
+}