feat(bp): IBattlePassService skeleton + level-curve method + DI

SVSim.EmulatedEntrypoint/Models/Dtos/BattlePassLevel.cs

@@ -3,13 +3,18 @@ using System.Text.Json.Serialization;
 
 namespace SVSim.EmulatedEntrypoint.Models.Dtos;
 
+/// <summary>
+/// One entry under <c>/load/index.battle_pass_level_info</c>. Per memory
+/// project_wire_key_serialization, wire ints are strings here — client parses them via .ToInt().
+/// </summary>
 [MessagePackObject]
 public class BattlePassLevel
 {
     [JsonPropertyName("level")]
     [Key("level")]
-    public int Level { get; set; }
+    public string Level { get; set; } = "";
+
     [JsonPropertyName("required_point")]
     [Key("required_point")]
-    public int RequiredPoints { get; set; }
-}
+    public string RequiredPoint { get; set; } = "";
+}