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

SVSim.EmulatedEntrypoint/Services/BattlePassBuyOutcome.cs

@@ -0,0 +1,14 @@
+using SVSim.Database.Services;
+
+namespace SVSim.EmulatedEntrypoint.Services;
+
+/// <summary>
+/// Result of <see cref="IBattlePassService.BuyPremiumAsync"/>. <c>AchievedRewards</c> = the
+/// delta that was just granted (goes into <c>achieved_info.battle_pass_reward_list</c>);
+/// <c>PostStateTotals</c> = post-state totals for affected goods (goes into <c>reward_list</c>),
+/// including the crystal deduction per memory project_wire_reward_list_post_state.
+/// </summary>
+public sealed record BattlePassBuyOutcome(
+    int ResultCode,
+    IReadOnlyList<GrantedReward> AchievedRewards,
+    IReadOnlyList<GrantedReward> PostStateTotals);