feat(Fundamentals): add fundamentals service

FinlyticFundamentals/Entities/FinancialStatementEntity.cs

@@ -0,0 +1,55 @@
+using System;
+using System.ComponentModel.DataAnnotations;
+using System.Text.Json.Serialization;
+
+namespace FinlyticFundamentals.Entities;
+
+/// <summary>
+/// Relational statement table linking historical Income Statements, Balance Sheets, and Cash Flow metrics.
+/// </summary>
+public class FinancialStatementEntity
+{
+    [Key]
+    public Guid Id { get; set; } = Guid.NewGuid();
+
+    [Required]
+    public string Isin { get; set; } = string.Empty;
+
+    [JsonIgnore]
+    public AssetFundamentalsEntity? AssetFundamentals { get; set; }
+
+    [Required]
+    public string PeriodType { get; set; } = string.Empty; // "Annual" or "Quarterly"
+
+    [Required]
+    public DateTime EndDate { get; set; }
+
+    // --- Income Statement Fields ---
+    public decimal? TotalRevenue { get; set; }
+    public decimal? CostOfRevenue { get; set; }
+    public decimal? GrossProfit { get; set; }
+    public decimal? OperatingExpenses { get; set; }
+    public decimal? OperatingIncome { get; set; }
+    public decimal? Ebitda { get; set; }
+    public decimal? NetIncome { get; set; }
+    public decimal? EpsBasic { get; set; }
+    public decimal? EpsDiluted { get; set; }
+
+    // --- Balance Sheet Fields ---
+    public decimal? CashAndCashEquivalents { get; set; }
+    public decimal? AccountsReceivable { get; set; }
+    public decimal? Inventory { get; set; }
+    public decimal? TotalCurrentAssets { get; set; }
+    public decimal? TotalNonCurrentAssets { get; set; }
+    public decimal? CurrentLiabilities { get; set; }
+    public decimal? LongTermDebt { get; set; }
+    public decimal? TotalLiabilities { get; set; }
+    public decimal? TotalStockholdersEquity { get; set; }
+
+    // --- Cash Flow Fields ---
+    public decimal? OperatingCashFlow { get; set; }
+    public decimal? InvestingCashFlow { get; set; }
+    public decimal? CapitalExpenditures { get; set; }
+    public decimal? FinancingCashFlow { get; set; }
+    public decimal? FreeCashFlow { get; set; } // OperatingCashFlow - CapEx
+}