Change to static skin catalog population

BlueLaminate/BlueLaminate.EFCore/Entities/Collection.cs

@@ -0,0 +1,21 @@
+namespace BlueLaminate.EFCore.Entities;
+
+/// <summary>
+/// A source a skin originates from: either an in-game collection (e.g.
+/// "The Dead Hand Collection") or a container/case (e.g. "Glove Case").
+/// </summary>
+public class Collection
+{
+    public int Id { get; set; }
+
+    public string Name { get; set; } = null!;
+
+    /// <summary>Stable id from the CSGO-API catalogue, e.g. "collection-set-community-37"
+    /// or "crate-4288". The natural key.</summary>
+    public string Slug { get; set; } = null!;
+
+    /// <summary>"Collection" or "Container".</summary>
+    public string Type { get; set; } = null!;
+
+    public ICollection<Skin> Skins { get; set; } = new List<Skin>();
+}

BlueLaminate/BlueLaminate.EFCore/Entities/Skin.cs

@@ -6,17 +6,29 @@ public class Skin
     public int WeaponId { get; set; }
     public Weapon Weapon { get; set; } = null!;
 
+    /// <summary>Stable id from the CSGO-API catalogue, e.g. "skin-e757fd7191f9". The natural key.</summary>
+    public string Slug { get; set; } = null!;
+
     public string Name { get; set; } = null!;
     public string Rarity { get; set; } = null!;
     public string? Description { get; set; }
     public string? ImageUrl { get; set; }
 
-    public decimal FloatMin { get; set; }
-    public decimal FloatMax { get; set; }
+    public bool StatTrakAvailable { get; set; }
+    public bool SouvenirAvailable { get; set; }
 
-    // Computed in the database: float_min = 0.0 AND float_max = 1.0.
-    // A skin with a capped float range behaves differently in tradeup calculations.
-    public bool TrueFloat { get; private set; }
+    /// <summary>Every collection and container this skin originates from.</summary>
+    public ICollection<Collection> Collections { get; set; } = new List<Collection>();
+
+    // Null when the catalogue gives no wear range (e.g. vanilla knives). Callers
+    // must treat null as "unknown", not as a full 0.0–1.0 range.
+    public decimal? FloatMin { get; set; }
+    public decimal? FloatMax { get; set; }
+
+    // Computed in the database: float_min = 0.0 AND float_max = 1.0; null while the
+    // bounds are unknown. A skin with a capped float range behaves differently in
+    // tradeup calculations.
+    public bool? TrueFloat { get; private set; }
 
     public ICollection<SkinCondition> Conditions { get; set; } = new List<SkinCondition>();
     public ICollection<SkinInstance> Instances { get; set; } = new List<SkinInstance>();