fix: перенёс уровни в бд и пофиксид их отображение на фронте

backend/UniVerse.Infrastructure/Migrations/20260517230001_LevelThresholds.cs

@@ -0,0 +1,58 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+#pragma warning disable CA1814 // Prefer jagged arrays over multidimensional
+
+namespace UniVerse.Infrastructure.Migrations
+{
+    /// <inheritdoc />
+    public partial class LevelThresholds : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.CreateTable(
+                name: "level_thresholds",
+                columns: table => new
+                {
+                    level = table.Column<int>(type: "integer", nullable: false),
+                    required_xp = table.Column<int>(type: "integer", nullable: false)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_level_thresholds", x => x.level);
+                    table.CheckConstraint("CK_level_thresholds_level_positive", "level > 0");
+                    table.CheckConstraint("CK_level_thresholds_required_xp_non_negative", "required_xp >= 0");
+                });
+
+            migrationBuilder.InsertData(
+                table: "level_thresholds",
+                columns: new[] { "level", "required_xp" },
+                values: new object[,]
+                {
+                    { 1, 0 },
+                    { 2, 100 },
+                    { 3, 300 },
+                    { 4, 600 },
+                    { 5, 1000 },
+                    { 6, 1500 },
+                    { 7, 2500 },
+                    { 8, 4000 }
+                });
+
+            migrationBuilder.CreateIndex(
+                name: "IX_level_thresholds_required_xp",
+                table: "level_thresholds",
+                column: "required_xp",
+                unique: true);
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropTable(
+                name: "level_thresholds");
+        }
+    }
+}