Add TCPA-compliant SMS consent tracking for prospect quotes

- Quote entity: ProspectSmsConsent (bool) + ProspectSmsConsentedAt (DateTime?) fields
- QuoteDtos: consent fields on Create/Update/Convert DTOs with TCPA guidance text
- Quote Create/Edit views: SMS consent checkbox shown when mobile number is entered
- Quote ConvertToCustomer view: staff must re-confirm consent carries over to customer record
- QuoteApproval: consent state exposed in ViewModel and ApprovalPage for transparency
- Consent timestamp cleared when prospect quote is linked to an existing customer
- Migration: AddProspectSmsConsent

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

src/PowderCoating.Web/ViewModels/QuoteApprovalViewModel.cs

@@ -12,6 +12,10 @@ public class QuoteApprovalViewModel
     public string? CustomerEmail { get; set; }
     public DateTime? ExpirationDate { get; set; }
     public DateTime? ApprovalTokenExpiresAt { get; set; }
+    public decimal ItemsSubtotal { get; set; }
+    public decimal OvenBatchCost { get; set; }
+    public decimal ShopSuppliesAmount { get; set; }
+    public decimal ShopSuppliesPercent { get; set; }
     public decimal SubTotal { get; set; }
     public decimal DiscountAmount { get; set; }
     public bool HideDiscountFromCustomer { get; set; }