refactor(bp): flatten BattlePassLevelEntry — drop misnamed RewardData jsonb

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

SVSim.Database/Models/BattlePassLevelEntry.cs

@@ -1,16 +1,13 @@
-using System.ComponentModel.DataAnnotations.Schema;
 using SVSim.Database.Common;
 
 namespace SVSim.Database.Models;
 
 /// <summary>
-/// One battle pass level (1-100). RewardData jsonb holds the per-level reward blob from
-/// /load/index data.battle_pass_level_info[level]. Shape varies per level so we preserve verbatim.
+/// One battle pass level (1..100). Mirrors a single entry in /load/index.battle_pass_level_info.
+/// Curve is global, immutable per deploy; cached by IBattlePassService.
 /// </summary>
 public class BattlePassLevelEntry : BaseEntity<int>
 {
     public int Level { get => Id; set => Id = value; }
-
-    [Column(TypeName = "jsonb")]
-    public string RewardData { get; set; } = "{}";
+    public int RequiredPoint { get; set; }
 }