Add facility overhead (rent + utilities) to operating costs and pricing engine

Adds MonthlyRent, MonthlyUtilities, and MonthlyBillableHours to CompanyOperatingCosts so fixed shop occupancy costs are recovered on every quote. The pricing engine converts these into a per-hour rate and applies it as a transparent "Facility Overhead" line between oven batch cost and shop supplies. UI added in Company Settings Operating Costs tab and Setup Wizard Step 3; migration AddFacilityOverheadFields applied. Help docs and AI knowledge base updated to cover the new fields and the revised quote pricing calculation order.

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

src/PowderCoating.Application/DTOs/Quote/QuoteDtos.cs

@@ -606,6 +606,9 @@ public class QuotePricingBreakdownDto
     public int OvenBatches { get; set; }
     public int OvenCycleMinutes { get; set; }
 
+    public decimal FacilityOverheadCost { get; set; }
+    public decimal FacilityOverheadRatePerHour { get; set; }
+
     public decimal Total { get; set; }
 
     // Cost Breakdown Details
@@ -822,6 +825,10 @@ public class QuotePricingResult
     public int OvenBatches { get; set; }
     public int OvenCycleMinutes { get; set; }
 
+    // Facility overhead (rent + utilities apportioned by estimated job hours)
+    public decimal FacilityOverheadCost { get; set; }
+    public decimal FacilityOverheadRatePerHour { get; set; }
+
     // Detailed breakdown for transparency
     public decimal MaterialCosts { get; set; }
     public decimal LaborCosts { get; set; }