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src/PowderCoating.Core/Entities/PowderUsageLog.cs

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+namespace PowderCoating.Core.Entities;
+
+/// <summary>
+/// Records actual powder consumption against a specific coat on a job.
+/// Links the InventoryTransaction (the deduction) to the JobItemCoat (what the powder was used on).
+/// This is the bridge that enables prediction vs actual reporting per powder SKU.
+/// </summary>
+public class PowderUsageLog : BaseEntity
+{
+    public int JobId { get; set; }
+    public int JobItemId { get; set; }
+    public int JobItemCoatId { get; set; }
+    public int? InventoryItemId { get; set; }           // null for custom/vendor powder
+    public int? InventoryTransactionId { get; set; }    // FK to the inventory deduction (if auto-linked)
+
+    public decimal ActualLbsUsed { get; set; }
+    public decimal EstimatedLbs { get; set; }           // Snapshot of PowderToOrder at time of recording
+    public decimal VarianceLbs { get; set; }            // ActualLbsUsed - EstimatedLbs (positive = used more than estimated)
+
+    public string RecordedByUserId { get; set; } = string.Empty;
+    public DateTime RecordedAt { get; set; } = DateTime.UtcNow;
+    public string? Notes { get; set; }
+
+    // Navigation
+    public virtual Job Job { get; set; } = null!;
+    public virtual JobItem JobItem { get; set; } = null!;
+    public virtual JobItemCoat JobItemCoat { get; set; } = null!;
+    public virtual InventoryItem? InventoryItem { get; set; }
+    public virtual InventoryTransaction? InventoryTransaction { get; set; }
+}