feat: implement CRM and tax accounting specialized services and repositories

Phase 2: Repository Implementation (Dapper)
- TaxProfileRepository: tax profile CRUD + risk level analysis + filing due dates
- TaxFilingScheduleRepository: schedule tracking + upcoming due dates + completion marking
- ConsultingActivityRepository: CRM activity history + pending followups + consultant tracking
- ContractRepository: contract lifecycle + active contracts + expiring alerts + MRR calculation
- RevenueTrackingRepository: invoice tracking + payment status + revenue analysis

Phase 3: Service Layer (Business Logic)
- TaxProfileService: profile creation, risk assessment, upcoming filing detection
- TaxFilingScheduleService: schedule management, deadline tracking, completion workflow
- ConsultingActivityService: activity logging, followup management, consultant productivity
- ContractService: contract management, MRR calculation, expiring contract alerts
- RevenueTrackingService: invoice creation, payment tracking, revenue analytics

Phase 4: API Controller (REST Endpoints)
- TaxProfileController: CRUD operations + high-risk filtering + upcoming filings query

Architecture Highlights:
- SOLID principles: each layer has clear responsibility
- Dapper-based repositories for data access
- Comprehensive service layer for business logic
- RESTful API design with proper error handling
- Ready for Blazor UI implementation and deployment

Database Migration V015 executed:
- 5 new specialized tables for CRM and tax accounting
- Appropriate indexes for query performance
- Foreign key constraints for data integrity

TaxBaik.Application/DependencyInjection.cs

@@ -20,6 +20,11 @@ public static class DependencyInjection
         services.AddScoped<ConsultationService>();
         services.AddScoped<TaxFilingService>();
         services.AddScoped<CompanyService>();
+        services.AddScoped<TaxProfileService>();
+        services.AddScoped<TaxFilingScheduleService>();
+        services.AddScoped<ConsultingActivityService>();
+        services.AddScoped<ContractService>();
+        services.AddScoped<RevenueTrackingService>();
         return services;
     }
 }

TaxBaik.Application/Services/ConsultingActivityService.cs

@@ -0,0 +1,47 @@
+namespace TaxBaik.Application.Services;
+
+using TaxBaik.Domain.Entities;
+using TaxBaik.Domain.Interfaces;
+
+public class ConsultingActivityService(IConsultingActivityRepository repository)
+{
+    public async Task<int> CreateAsync(int clientId, string activityType, DateTime activityDate,
+        string description, int? consultantId = null, DateTime? nextFollowupDate = null, CancellationToken ct = default)
+    {
+        if (clientId <= 0)
+            throw new ValidationException("유효한 고객을 선택하세요.");
+        if (string.IsNullOrWhiteSpace(activityType))
+            throw new ValidationException("활동 유형을 입력하세요.");
+        if (string.IsNullOrWhiteSpace(description))
+            throw new ValidationException("활동 내용을 입력하세요.");
+
+        var activity = new ConsultingActivity
+        {
+            ClientId = clientId,
+            ActivityType = activityType.Trim(),
+            ActivityDate = activityDate,
+            Description = description.Trim(),
+            AssignedConsultantId = consultantId,
+            NextFollowupDate = nextFollowupDate,
+            CreatedAt = DateTime.UtcNow,
+            UpdatedAt = DateTime.UtcNow
+        };
+
+        return await repository.CreateAsync(activity, ct);
+    }
+
+    public async Task<IEnumerable<ConsultingActivity>> GetByClientIdAsync(int clientId, CancellationToken ct = default) =>
+        await repository.GetByClientIdAsync(clientId, ct);
+
+    public async Task<IEnumerable<ConsultingActivity>> GetPendingFollowupsAsync(CancellationToken ct = default) =>
+        await repository.GetPendingFollowupsAsync(ct);
+
+    public async Task<IEnumerable<ConsultingActivity>> GetConsultantActivityAsync(int consultantId, DateTime fromDate, CancellationToken ct = default) =>
+        await repository.GetByConsultantAsync(consultantId, fromDate, ct);
+
+    public async Task UpdateAsync(int id, string? outcome, DateTime? nextFollowupDate, CancellationToken ct = default)
+    {
+        var activity = new ConsultingActivity { Id = id, Outcome = outcome, NextFollowupDate = nextFollowupDate, UpdatedAt = DateTime.UtcNow };
+        await repository.UpdateAsync(activity, ct);
+    }
+}

TaxBaik.Application/Services/ContractService.cs

@@ -0,0 +1,50 @@
+namespace TaxBaik.Application.Services;
+
+using TaxBaik.Domain.Entities;
+using TaxBaik.Domain.Interfaces;
+
+public class ContractService(IContractRepository repository)
+{
+    public async Task<int> CreateAsync(int clientId, string contractNumber, string serviceType,
+        DateTime startDate, decimal? monthlyFee = null, decimal? totalAmount = null, CancellationToken ct = default)
+    {
+        if (clientId <= 0)
+            throw new ValidationException("유효한 고객을 선택하세요.");
+        if (string.IsNullOrWhiteSpace(contractNumber))
+            throw new ValidationException("계약 번호를 입력하세요.");
+        if (string.IsNullOrWhiteSpace(serviceType))
+            throw new ValidationException("서비스 유형을 입력하세요.");
+
+        var contract = new Contract
+        {
+            ClientId = clientId,
+            ContractNumber = contractNumber.Trim(),
+            ServiceType = serviceType.Trim(),
+            ContractDate = DateTime.Today,
+            StartDate = startDate,
+            MonthlyFee = monthlyFee,
+            TotalAmount = totalAmount,
+            Status = "active",
+            PaymentStatus = "pending",
+            CreatedAt = DateTime.UtcNow,
+            UpdatedAt = DateTime.UtcNow
+        };
+
+        return await repository.CreateAsync(contract, ct);
+    }
+
+    public async Task<Contract?> GetByIdAsync(int id, CancellationToken ct = default) =>
+        await repository.GetByIdAsync(id, ct);
+
+    public async Task<IEnumerable<Contract>> GetByClientIdAsync(int clientId, CancellationToken ct = default) =>
+        await repository.GetByClientIdAsync(clientId, ct);
+
+    public async Task<IEnumerable<Contract>> GetActiveContractsAsync(CancellationToken ct = default) =>
+        await repository.GetActiveContractsAsync(ct);
+
+    public async Task<IEnumerable<Contract>> GetExpiringContractsAsync(int daysAhead = 30, CancellationToken ct = default) =>
+        await repository.GetExpiringContractsAsync(daysAhead, ct);
+
+    public async Task<decimal> GetMonthlyRecurringRevenueAsync(CancellationToken ct = default) =>
+        await repository.GetMonthlyRecurringRevenueAsync(ct);
+}

TaxBaik.Application/Services/RevenueTrackingService.cs

@@ -0,0 +1,52 @@
+namespace TaxBaik.Application.Services;
+
+using TaxBaik.Domain.Entities;
+using TaxBaik.Domain.Interfaces;
+
+public class RevenueTrackingService(IRevenueTrackingRepository repository)
+{
+    public async Task<int> CreateAsync(int clientId, string invoiceNumber, DateTime invoiceDate,
+        decimal amount, string? serviceType = null, DateTime? dueDate = null, CancellationToken ct = default)
+    {
+        if (clientId <= 0)
+            throw new ValidationException("유효한 고객을 선택하세요.");
+        if (string.IsNullOrWhiteSpace(invoiceNumber))
+            throw new ValidationException("인보이스 번호를 입력하세요.");
+        if (amount <= 0)
+            throw new ValidationException("금액은 0보다 커야 합니다.");
+
+        var revenue = new RevenueTracking
+        {
+            ClientId = clientId,
+            InvoiceNumber = invoiceNumber.Trim(),
+            InvoiceDate = invoiceDate,
+            Amount = amount,
+            ServiceType = string.IsNullOrWhiteSpace(serviceType) ? null : serviceType.Trim(),
+            DueDate = dueDate,
+            PaymentStatus = "pending",
+            CreatedAt = DateTime.UtcNow,
+            UpdatedAt = DateTime.UtcNow
+        };
+
+        return await repository.CreateAsync(revenue, ct);
+    }
+
+    public async Task<IEnumerable<RevenueTracking>> GetByClientIdAsync(int clientId, CancellationToken ct = default) =>
+        await repository.GetByClientIdAsync(clientId, ct);
+
+    public async Task<IEnumerable<RevenueTracking>> GetPendingPaymentsAsync(CancellationToken ct = default) =>
+        await repository.GetPendingPaymentsAsync(ct);
+
+    public async Task<IEnumerable<RevenueTracking>> GetMonthlyRevenueAsync(DateTime month, CancellationToken ct = default)
+    {
+        var startDate = new DateTime(month.Year, month.Month, 1);
+        var endDate = startDate.AddMonths(1).AddDays(-1);
+        return await repository.GetByDateRangeAsync(startDate, endDate, ct);
+    }
+
+    public async Task MarkPaidAsync(int id, DateTime paymentDate, CancellationToken ct = default) =>
+        await repository.MarkPaidAsync(id, paymentDate, ct);
+
+    public async Task<decimal> GetTotalRevenueAsync(DateTime startDate, DateTime endDate, CancellationToken ct = default) =>
+        await repository.GetTotalRevenueAsync(startDate, endDate, ct);
+}

TaxBaik.Application/Services/TaxFilingScheduleService.cs

@@ -0,0 +1,50 @@
+namespace TaxBaik.Application.Services;
+
+using TaxBaik.Domain.Entities;
+using TaxBaik.Domain.Interfaces;
+
+public class TaxFilingScheduleService(ITaxFilingScheduleRepository repository)
+{
+    public async Task<int> CreateAsync(int clientId, string filingType, DateTime dueDate, int filingYear,
+        int? assignedToId = null, CancellationToken ct = default)
+    {
+        if (clientId <= 0)
+            throw new ValidationException("유효한 고객을 선택하세요.");
+        if (string.IsNullOrWhiteSpace(filingType))
+            throw new ValidationException("신고 유형을 입력하세요.");
+        if (dueDate < DateTime.Today)
+            throw new ValidationException("마감일은 오늘 이후여야 합니다.");
+
+        var schedule = new TaxFilingSchedule
+        {
+            ClientId = clientId,
+            FilingType = filingType.Trim(),
+            DueDate = dueDate,
+            FilingYear = filingYear,
+            Status = "pending",
+            AssignedToId = assignedToId,
+            CreatedAt = DateTime.UtcNow,
+            UpdatedAt = DateTime.UtcNow
+        };
+
+        return await repository.CreateAsync(schedule, ct);
+    }
+
+    public async Task<TaxFilingSchedule?> GetByIdAsync(int id, CancellationToken ct = default) =>
+        await repository.GetByIdAsync(id, ct);
+
+    public async Task<IEnumerable<TaxFilingSchedule>> GetByClientIdAsync(int clientId, CancellationToken ct = default) =>
+        await repository.GetByClientIdAsync(clientId, ct);
+
+    public async Task<IEnumerable<TaxFilingSchedule>> GetUpcomingDuesAsync(int daysAhead = 30, CancellationToken ct = default) =>
+        await repository.GetUpcomingDuesAsync(daysAhead, ct);
+
+    public async Task MarkCompletedAsync(int id, CancellationToken ct = default) =>
+        await repository.MarkCompletedAsync(id, ct);
+
+    public async Task<int> GetPendingCountAsync(CancellationToken ct = default)
+    {
+        var pending = await repository.GetByStatusAsync("pending", ct);
+        return pending.Count();
+    }
+}

TaxBaik.Application/Services/TaxProfileService.cs

@@ -0,0 +1,58 @@
+namespace TaxBaik.Application.Services;
+
+using TaxBaik.Domain.Entities;
+using TaxBaik.Domain.Interfaces;
+
+public class TaxProfileService(ITaxProfileRepository repository)
+{
+    public async Task<int> CreateAsync(int clientId, string? businessType, string? businessRegistration = null,
+        string? accountingMethod = null, DateTime? establishmentDate = null, CancellationToken ct = default)
+    {
+        if (clientId <= 0)
+            throw new ValidationException("유효한 고객을 선택하세요.");
+        if (string.IsNullOrWhiteSpace(businessType))
+            throw new ValidationException("사업 유형을 입력하세요.");
+
+        var profile = new TaxProfile
+        {
+            ClientId = clientId,
+            BusinessType = businessType.Trim(),
+            BusinessRegistration = string.IsNullOrWhiteSpace(businessRegistration) ? null : businessRegistration.Trim(),
+            EstablishmentDate = establishmentDate,
+            AccountingMethod = string.IsNullOrWhiteSpace(accountingMethod) ? null : accountingMethod.Trim(),
+            TaxRiskLevel = "normal",
+            CreatedAt = DateTime.UtcNow,
+            UpdatedAt = DateTime.UtcNow
+        };
+
+        return await repository.CreateAsync(profile, ct);
+    }
+
+    public async Task<TaxProfile?> GetByClientIdAsync(int clientId, CancellationToken ct = default) =>
+        await repository.GetByClientIdAsync(clientId, ct);
+
+    public async Task UpdateAsync(int profileId, string? businessType, string? accountingMethod,
+        DateTime? nextFilingDueDate, string taxRiskLevel = "normal", CancellationToken ct = default)
+    {
+        var profile = new TaxProfile { Id = profileId };
+        if (!string.IsNullOrWhiteSpace(businessType))
+            profile.BusinessType = businessType.Trim();
+        if (!string.IsNullOrWhiteSpace(accountingMethod))
+            profile.AccountingMethod = accountingMethod.Trim();
+        profile.NextFilingDueDate = nextFilingDueDate;
+        profile.TaxRiskLevel = taxRiskLevel;
+        profile.UpdatedAt = DateTime.UtcNow;
+
+        await repository.UpdateAsync(profile, ct);
+    }
+
+    public async Task<IEnumerable<TaxProfile>> GetHighRiskProfilesAsync(CancellationToken ct = default) =>
+        await repository.GetByRiskLevelAsync("high", ct);
+
+    public async Task<IEnumerable<TaxProfile>> GetUpcomingFilingDuesAsync(int daysAhead = 30, CancellationToken ct = default)
+    {
+        var startDate = DateTime.Today;
+        var endDate = startDate.AddDays(daysAhead);
+        return await repository.GetUpcomingFilingDuesAsync(startDate, endDate, ct);
+    }
+}