feat(missions): /load/index materializes viewer mission/achievement state

EnsureCurrentAsync now takes viewerId (was Viewer), so it works with
LoadController's AsNoTracking-loaded detached viewers.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

SVSim.EmulatedEntrypoint/Controllers/LoadController.cs

@@ -1,5 +1,6 @@
 using System.Text.Json;
 using Microsoft.AspNetCore.Mvc;
+using SVSim.Database;
 using SVSim.Database.Enums;
 using SVSim.Database.Models;
 using SVSim.Database.Models.Config;
@@ -47,11 +48,14 @@ public class LoadController : SVSimController
     private readonly ICardAcquisitionService _acquisition;
     private readonly IGameConfigService _config;
     private readonly IBattlePassService _battlePass;
+    private readonly IViewerMissionStateService _missionState;
+    private readonly SVSimDbContext _db;
 
     public LoadController(IViewerRepository viewerRepository, ICardRepository cardRepository,
         ICollectionRepository collectionRepository, IGlobalsRepository globalsRepository,
         ICardAcquisitionService acquisition, IGameConfigService config,
-        IBattlePassService battlePass)
+        IBattlePassService battlePass, IViewerMissionStateService missionState,
+        SVSimDbContext db)
     {
         _viewerRepository = viewerRepository;
         _cardRepository = cardRepository;
@@ -60,6 +64,8 @@ public class LoadController : SVSimController
         _acquisition = acquisition;
         _config = config;
         _battlePass = battlePass;
+        _missionState = missionState;
+        _db = db;
     }
 
     [HttpPost("index")]
@@ -83,6 +89,11 @@ public class LoadController : SVSimController
         // (on a separate tracked instance) won't appear on this snapshot. Without the re-fetch,
         // the response payload would be one /load/index behind on newly-granted cosmetics.
         await _acquisition.BackfillCosmeticsAsync(viewer.Id);
+
+        // Lazy-materialize mission/achievement state. Idempotent — safe to call every /load/index.
+        await _missionState.EnsureCurrentAsync(viewer.Id);
+        await _db.SaveChangesAsync();
+
         viewer = await _viewerRepository.GetViewerByShortUdid(shortUdid);
         if (viewer is null)
         {