重构预算管理模块，添加预算记录和服务，更新相关API，优化预算统计逻辑

Service/BudgetService.cs

@@ -0,0 +1,94 @@
+namespace Service;
+
+public interface IBudgetService
+{
+    Task<List<BudgetRecord>> GetAllAsync();
+    Task<BudgetRecord?> GetByIdAsync(long id);
+    Task<bool> AddAsync(BudgetRecord budget);
+    Task<bool> DeleteAsync(long id);
+    Task<bool> UpdateAsync(BudgetRecord budget);
+    Task<decimal> CalculateCurrentAmountAsync(BudgetRecord budget, DateTime? now = null);
+    Task<bool> ToggleStopAsync(long id);
+}
+
+public class BudgetService(
+    IBudgetRepository budgetRepository,
+    ILogger<BudgetService> logger) : IBudgetService
+{
+    public async Task<List<BudgetRecord>> GetAllAsync()
+    {
+        var list = await budgetRepository.GetAllAsync();
+        return list.ToList();
+    }
+
+    public async Task<BudgetRecord?> GetByIdAsync(long id)
+    {
+        return await budgetRepository.GetByIdAsync(id);
+    }
+
+    public async Task<bool> AddAsync(BudgetRecord budget)
+    {
+        return await budgetRepository.AddAsync(budget);
+    }
+
+    public async Task<bool> DeleteAsync(long id)
+    {
+        return await budgetRepository.DeleteAsync(id);
+    }
+
+    public async Task<bool> UpdateAsync(BudgetRecord budget)
+    {
+        return await budgetRepository.UpdateAsync(budget);
+    }
+
+    public async Task<bool> ToggleStopAsync(long id)
+    {
+        var budget = await budgetRepository.GetByIdAsync(id);
+        if (budget == null) return false;
+        budget.IsStopped = !budget.IsStopped;
+        return await budgetRepository.UpdateAsync(budget);
+    }
+
+    public async Task<decimal> CalculateCurrentAmountAsync(BudgetRecord budget, DateTime? now = null)
+    {
+        if (budget.IsStopped) return 0;
+
+        var referenceDate = now ?? DateTime.Now;
+        var (startDate, endDate) = GetPeriodRange(budget.StartDate, budget.Type, referenceDate);
+
+        return await budgetRepository.GetCurrentAmountAsync(budget, startDate, endDate);
+    }
+
+    public static (DateTime start, DateTime end) GetPeriodRange(DateTime startDate, BudgetPeriodType type, DateTime referenceDate)
+    {
+        if (type == BudgetPeriodType.Longterm) return (startDate, DateTime.MaxValue);
+
+        DateTime start;
+        DateTime end;
+
+        if (type == BudgetPeriodType.Week)
+        {
+            var daysFromStart = (referenceDate.Date - startDate.Date).Days;
+            var weeksFromStart = daysFromStart / 7;
+            start = startDate.Date.AddDays(weeksFromStart * 7);
+            end = start.AddDays(6).AddHours(23).AddMinutes(59).AddSeconds(59);
+        }
+        else if (type == BudgetPeriodType.Month)
+        {
+            start = new DateTime(referenceDate.Year, referenceDate.Month, 1);
+            end = start.AddMonths(1).AddDays(-1).AddHours(23).AddMinutes(59).AddSeconds(59);
+        }
+        else if (type == BudgetPeriodType.Year)
+        {
+            start = new DateTime(referenceDate.Year, 1, 1);
+            end = new DateTime(referenceDate.Year, 12, 31).AddHours(23).AddMinutes(59).AddSeconds(59);
+        }
+        else
+        {
+            start = startDate;
+            end = DateTime.MaxValue;
+        }
+
+        return (start, end);
+    }
+}