feat: Add Customer field to Project entity

Adds a customer name field to projects for better job tracking and
identification on reports.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

CutList.Web/Data/Entities/Project.cs

@@ -4,14 +4,12 @@ public class Project
 {
     public int Id { get; set; }
     public string Name { get; set; } = string.Empty;
-    public int? MaterialId { get; set; }
+    public string? Customer { get; set; }
     public int? CuttingToolId { get; set; }
     public string? Notes { get; set; }
     public DateTime CreatedAt { get; set; } = DateTime.UtcNow;
     public DateTime? UpdatedAt { get; set; }
 
-    public Material? Material { get; set; }
     public CuttingTool? CuttingTool { get; set; }
     public ICollection<ProjectPart> Parts { get; set; } = new List<ProjectPart>();
-    public ICollection<ProjectStockBin> StockBins { get; set; } = new List<ProjectStockBin>();
 }