Add world delta streaming and viewer smoothing

apps/backend/Simulation/RuntimeModels.cs

@@ -13,6 +13,7 @@ public sealed class SimulationWorld
   public required List<ShipRuntime> Ships { get; init; }
   public required List<FactionRuntime> Factions { get; init; }
   public required Dictionary<string, ShipDefinition> ShipDefinitions { get; init; }
+  public int TickIntervalMs { get; init; } = 200;
   public DateTimeOffset GeneratedAtUtc { get; set; }
 }
 
@@ -30,6 +31,7 @@ public sealed class ResourceNodeRuntime
   public required string ItemId { get; init; }
   public float OreRemaining { get; set; }
   public float MaxOre { get; init; }
+  public string LastDeltaSignature { get; set; } = string.Empty;
 }
 
 public sealed class StationRuntime
@@ -43,6 +45,7 @@ public sealed class StationRuntime
   public float RefinedStock { get; set; }
   public float ProcessTimer { get; set; }
   public HashSet<string> DockedShipIds { get; } = [];
+  public string LastDeltaSignature { get; set; } = string.Empty;
 }
 
 public sealed class ShipRuntime
@@ -53,6 +56,7 @@ public sealed class ShipRuntime
   public required string FactionId { get; init; }
   public required Vector3 Position { get; set; }
   public required Vector3 TargetPosition { get; set; }
+  public Vector3 Velocity { get; set; } = Vector3.Zero;
   public string State { get; set; } = "idle";
   public ShipOrderRuntime? Order { get; set; }
   public required DefaultBehaviorRuntime DefaultBehavior { get; set; }
@@ -63,6 +67,7 @@ public sealed class ShipRuntime
   public float Health { get; set; }
   public List<string> History { get; } = [];
   public string LastSignature { get; set; } = string.Empty;
+  public string LastDeltaSignature { get; set; } = string.Empty;
 }
 
 public sealed class FactionRuntime
@@ -75,6 +80,7 @@ public sealed class FactionRuntime
   public float GoodsProduced { get; set; }
   public int ShipsBuilt { get; set; }
   public int ShipsLost { get; set; }
+  public string LastDeltaSignature { get; set; } = string.Empty;
 }
 
 public sealed class ShipOrderRuntime
@@ -131,4 +137,16 @@ public readonly record struct Vector3(float X, float Y, float Z)
       Y + ((target.Y - Y) * t),
       Z + ((target.Z - Z) * t));
   }
+
+  public Vector3 Subtract(Vector3 other) => new(X - other.X, Y - other.Y, Z - other.Z);
+
+  public Vector3 Divide(float value)
+  {
+    if (value == 0f)
+    {
+      return Zero;
+    }
+
+    return new(X / value, Y / value, Z / value);
+  }
 }