Ad-hoc quote email, accounting improvements, AI lookup fix, and misc service updates

- Quotes: ad-hoc email modal on Quote Details lets staff send to an address not on file;
  QuotesController passes overrideEmail through to NotificationService
- Quotes/Details view: SMS consent display, email/SMS send button state based on consent
- Accounting module: AccountingDisplayHelpers for consistent ledger formatting;
  AccountsController + Accounts views improvements; AccountingEnums additions
- Bills/Expenses: AI account categorization fixes in BillsController and ExpensesController
- InventoryAiLookupService: TDS cure fallback no longer fires on AiAugmentFromUrl path
  (LookupByUrlAsync already has it built in — was double-fetching)
- PdfService: quote/invoice PDF updates
- PricingCalculationService: minor pricing logic fix
- QuoteProfile: mapping updates for new quote fields
- ApplicationDbContextModelSnapshot: catches up to all 4 migrations in this branch

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

src/PowderCoating.Application/Services/PdfService.cs

@@ -98,7 +98,12 @@ public class PdfService : IPdfService
                     page.DefaultTextStyle(x => x.FontSize(10).FontFamily("Arial"));
 
                     page.Header().Element(c => ComposeInvoiceHeader(c, companyLogo, companyInfo, accentColor, invoiceDto));
-                    page.Content().Element(c => ComposeInvoiceContent(c, invoiceDto, accentColor, template));
+                    page.Content().Layers(layers =>
+                    {
+                        layers.PrimaryLayer().Element(c => ComposeInvoiceContent(c, invoiceDto, accentColor, template));
+                        if (invoiceDto.Status == InvoiceStatus.Paid)
+                            layers.Layer().Element(c => ComposePaidStamp(c));
+                    });
                     page.Footer().AlignCenter().Text(text =>
                     {
                         text.CurrentPageNumber();
@@ -153,7 +158,6 @@ public class PdfService : IPdfService
                     if (invoice.DueDate.HasValue)
                         column.Item().Text($"Due: {invoice.DueDate.Value:MMMM d, yyyy}").FontSize(9).FontColor(
                             invoice.Status == Core.Enums.InvoiceStatus.Overdue ? Colors.Red.Medium : Colors.Grey.Darken2);
-                    column.Item().Text($"Status: {invoice.Status}").FontSize(9);
                 });
             });
 
@@ -161,6 +165,27 @@ public class PdfService : IPdfService
         });
     }
 
+    /// <summary>
+    /// Renders a semi-transparent angled PAID stamp centred over the invoice content layer.
+    /// Uses QuestPDF layout primitives (AlignCenter, AlignMiddle, Rotate, Opacity) so no
+    /// external Skia/SkiaSharp dependency is needed.
+    /// </summary>
+    private static void ComposePaidStamp(IContainer container)
+    {
+        container
+            .AlignCenter()
+            .AlignMiddle()
+            .Rotate(-45f)
+            .Border(5)
+            .BorderColor(Colors.Green.Darken2)
+            .PaddingVertical(14)
+            .PaddingHorizontal(28)
+            .Text("PAID")
+            .FontSize(80)
+            .Bold()
+            .FontColor(Colors.Green.Darken2);
+    }
+
     /// <summary>
     /// Composes the body of the invoice PDF: bill-to address block, job reference, alternating-row
     /// line-item table, and a right-aligned totals block that conditionally shows discount, tax,