feat(missions): add 3 viewer entities + Viewer collections

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

SVSim.Database/Models/Viewer.cs

@@ -59,6 +59,12 @@ public class Viewer : BaseEntity<long>
 
     public List<ViewerBuildDeckProductPurchase> BuildDeckPurchases { get; set; } = new List<ViewerBuildDeckProductPurchase>();
 
+    public List<ViewerMission> Missions { get; set; } = new List<ViewerMission>();
+
+    public List<ViewerAchievement> Achievements { get; set; } = new List<ViewerAchievement>();
+
+    public List<ViewerEventCounter> EventCounters { get; set; } = new List<ViewerEventCounter>();
+
     #endregion
 
     #region Navigation Properties

SVSim.Database/Models/ViewerAchievement.cs

@@ -0,0 +1,17 @@
+namespace SVSim.Database.Models;
+
+/// <summary>
+/// Per-viewer state for one achievement type. Composite PK (ViewerId, AchievementType) configured
+/// in DbContext. <c>Level</c> is the viewer's current tier; <c>max_level</c> on the wire is
+/// derived from catalog as MAX(Level) per type. Lazy-created at /load/index time — one row per
+/// AchievementCatalogEntries.AchievementType that the viewer doesn't yet have a row for.
+/// </summary>
+public class ViewerAchievement
+{
+    public long ViewerId { get; set; }
+    public int AchievementType { get; set; }
+    public int Level { get; set; } = 1;
+    public int AchievementStatus { get; set; }
+    public int NowAchievedLevel { get; set; }
+    public int ResultAnnounceSawLevel { get; set; }
+}

SVSim.Database/Models/ViewerEventCounter.cs

@@ -0,0 +1,15 @@
+namespace SVSim.Database.Models;
+
+/// <summary>
+/// Per-viewer "how many times has this happened" counter. Composite PK
+/// (ViewerId, EventKey, Period). Period strings: "all-time", "month:YYYY-MM",
+/// "week:YYYY-W##", "day:YYYY-MM-DD" — all JST-anchored with 02:00 day-boundary.
+/// Single source of truth for total_count / done_number on every wire shape.
+/// </summary>
+public class ViewerEventCounter
+{
+    public long ViewerId { get; set; }
+    public string EventKey { get; set; } = "";
+    public string Period { get; set; } = "";
+    public int Count { get; set; }
+}

SVSim.Database/Models/ViewerMission.cs

@@ -0,0 +1,24 @@
+using System.ComponentModel.DataAnnotations.Schema;
+using SVSim.Database.Common;
+
+namespace SVSim.Database.Models;
+
+/// <summary>
+/// One assigned mission slot for a viewer. <c>Id</c> is the wire <c>UserMission.id</c> — echoed
+/// back as the retire-request parameter, auto-generated. Slot 0 = daily (lot_type=6),
+/// Slots 1..3 = weekly (lot_type=2). Progress (<c>total_count</c> on the wire) is NOT stored
+/// here — it's read from <see cref="ViewerEventCounter"/> at response-build time, keyed by the
+/// catalog row's EventType.
+/// </summary>
+public class ViewerMission : BaseEntity<long>
+{
+    [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
+    public override long Id { get; set; }
+
+    public long ViewerId { get; set; }
+    public int MissionCatalogId { get; set; }
+    public int Slot { get; set; }
+    public long AssignedAt { get; set; }
+    public long? ClaimedAt { get; set; }
+    public int MissionStatus { get; set; } = 1;
+}