Feat: System Prompts

- Se añade un sistema de prompts de gerarquía máxima para molder el asistente.
- Se añade control del sistema de prompts mediante el panel de administración.

ChatbotApi/Migrations/20251205154627_AddSystemPrompts.cs

@@ -0,0 +1,39 @@
+using System;
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace ChatbotApi.Migrations
+{
+    /// <inheritdoc />
+    public partial class AddSystemPrompts : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.CreateTable(
+                name: "SystemPrompts",
+                columns: table => new
+                {
+                    Id = table.Column<int>(type: "int", nullable: false)
+                        .Annotation("SqlServer:Identity", "1, 1"),
+                    Name = table.Column<string>(type: "nvarchar(100)", maxLength: 100, nullable: false),
+                    Content = table.Column<string>(type: "nvarchar(max)", nullable: false),
+                    IsActive = table.Column<bool>(type: "bit", nullable: false),
+                    CreatedAt = table.Column<DateTime>(type: "datetime2", nullable: false),
+                    UpdatedAt = table.Column<DateTime>(type: "datetime2", nullable: false)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_SystemPrompts", x => x.Id);
+                });
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropTable(
+                name: "SystemPrompts");
+        }
+    }
+}