Remove ShopWorker entity and migrate worker identity to ApplicationUser

Removes the ShopWorker and ShopWorkerRoleCost entities, all related DTOs,
mappings, controllers, views, and import/export paths. Worker identity is
now handled entirely through ApplicationUser with per-user LaborCostPerHour.
ShopWorkerRoleCosts table remains in production pending manual data migration.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/PowderCoating.Web/Program.cs

@@ -270,8 +270,7 @@ builder.Services.AddSingleton<IMapper>(sp =>
         cfg.AddProfile(new InventoryProfile());
         cfg.AddProfile(new EquipmentProfile());
         cfg.AddProfile(new MaintenanceProfile());
-        cfg.AddProfile(new ShopWorkerProfile());
-        cfg.AddProfile(new CatalogProfile());
+cfg.AddProfile(new CatalogProfile());
         cfg.AddProfile(new VendorProfile());
         cfg.AddProfile(new LookupProfile());
         cfg.AddProfile(new AppointmentProfile());