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.Infrastructure/TaxBaik.Infrastructure.csproj

@@ -2,6 +2,12 @@
   <ItemGroup>
     <ProjectReference Include="..\TaxBaik.Domain\TaxBaik.Domain.csproj" />
   </ItemGroup>
+  <ItemGroup>
+    <PackageReference Include="Dapper" Version="2.1.15" />
+    <PackageReference Include="Microsoft.Extensions.Configuration.Abstractions" Version="8.0.0" />
+    <PackageReference Include="Microsoft.Extensions.DependencyInjection" Version="8.0.0" />
+    <PackageReference Include="Npgsql" Version="8.0.1" />
+  </ItemGroup>
   <PropertyGroup>
     <TargetFramework>net8.0</TargetFramework>
     <Nullable>enable</Nullable>