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/Repositories/InquiryRepository.cs

@@ -0,0 +1,55 @@
+namespace TaxBaik.Infrastructure.Repositories;
+
+using Dapper;
+using TaxBaik.Domain.Entities;
+using TaxBaik.Domain.Interfaces;
+
+public class InquiryRepository(IDbConnectionFactory connectionFactory) : BaseRepository(connectionFactory), IInquiryRepository
+{
+    public async Task<int> CreateAsync(Inquiry inquiry, CancellationToken cancellationToken = default)
+    {
+        using var conn = Conn();
+        return await conn.QueryFirstAsync<int>(
+            @"INSERT INTO inquiries (name, phone, email, service_type, message, status, ip_address, created_at)
+              VALUES (@Name, @Phone, @Email, @ServiceType, @Message, @Status, @IpAddress, NOW())
+              RETURNING id",
+            inquiry);
+    }
+
+    public async Task<Inquiry?> GetByIdAsync(int id, CancellationToken cancellationToken = default)
+    {
+        using var conn = Conn();
+        return await conn.QueryFirstOrDefaultAsync<Inquiry>(
+            "SELECT id, name, phone, email, service_type, message, status, ip_address, created_at FROM inquiries WHERE id = @Id",
+            new { Id = id });
+    }
+
+    public async Task<(IEnumerable<Inquiry> Items, int Total)> GetPagedAsync(
+        int page, int pageSize, string? status = null, CancellationToken cancellationToken = default)
+    {
+        using var conn = Conn();
+        var offset = (page - 1) * pageSize;
+
+        using var reader = await conn.QueryMultipleAsync(
+            @"SELECT id, name, phone, email, service_type, message, status, ip_address, created_at
+              FROM inquiries
+              WHERE @Status::text IS NULL OR status = @Status
+              ORDER BY created_at DESC
+              LIMIT @PageSize OFFSET @Offset;
+
+              SELECT COUNT(*) FROM inquiries
+              WHERE @Status::text IS NULL OR status = @Status;",
+            new { Status = status, PageSize = pageSize, Offset = offset });
+
+        var items = (await reader.ReadAsync<Inquiry>()).ToList();
+        var total = await reader.ReadFirstAsync<int>();
+
+        return (items, total);
+    }
+
+    public async Task UpdateStatusAsync(int id, string status, CancellationToken cancellationToken = default)
+    {
+        using var conn = Conn();
+        await conn.ExecuteAsync("UPDATE inquiries SET status = @Status WHERE id = @Id", new { Id = id, Status = status });
+    }
+}