Inline item editing on details pages; fix Stripe receipt_email

Allow description, quantity, and price to be edited inline on Quote,
Job, and Invoice details pages without re-opening the wizard. Coating
and prep service rows remain read-only by design. Invoice editing is
gated to Draft/Sent/Overdue statuses; totals update live in the DOM.

Remove receipt_email from Stripe PaymentIntent creation so customers
can use any email they choose at checkout — Stripe validates format
and sends the receipt to whatever the customer enters in the Payment
Element, eliminating the risk of a stored email mismatch blocking a
payment from processing.

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

src/PowderCoating.Web/Controllers/InvoicesController.cs

@@ -3035,6 +3035,50 @@ public class InvoicesController : Controller
         return false;
     }
 
+    /// <summary>
+    /// Inline-edits description, quantity, and unit price on a single invoice line item.
+    /// Blocked on paid/voided invoices (same gate as the full Edit action).
+    /// Returns updated totals so the page can reflect the change without a reload.
+    /// </summary>
+    [HttpPost]
+    [ValidateAntiForgeryToken]
+    public async Task<IActionResult> PatchItem([FromBody] PatchInvoiceItemRequest request)
+    {
+        var currentUser = await _userManager.GetUserAsync(User);
+        if (currentUser == null) return Unauthorized();
+
+        var item = await _unitOfWork.InvoiceItems.GetByIdAsync(request.ItemId);
+        if (item == null) return NotFound();
+
+        var invoice = await _unitOfWork.Invoices.GetByIdAsync(item.InvoiceId);
+        if (invoice == null || invoice.CompanyId != currentUser.CompanyId) return NotFound();
+
+        if (invoice.Status is not (InvoiceStatus.Draft or InvoiceStatus.Sent or InvoiceStatus.Overdue))
+            return BadRequest(new { error = "Cannot edit items on a paid or voided invoice." });
+
+        item.Description = request.Description.Trim();
+        item.Quantity    = request.Quantity;
+        item.UnitPrice   = request.UnitPrice;
+        item.TotalPrice  = Math.Round(request.Quantity * request.UnitPrice, 2);
+        await _unitOfWork.InvoiceItems.UpdateAsync(item);
+
+        var allItems    = await _unitOfWork.InvoiceItems.FindAsync(ii => ii.InvoiceId == invoice.Id);
+        var newSubTotal = allItems.Sum(i => i.TotalPrice);
+        invoice.SubTotal   = newSubTotal;
+        invoice.TaxAmount  = Math.Round(newSubTotal * invoice.TaxPercent / 100m, 2);
+        invoice.Total      = Math.Round(newSubTotal - invoice.DiscountAmount + invoice.TaxAmount, 2);
+        await _unitOfWork.Invoices.UpdateAsync(invoice);
+        await _unitOfWork.CompleteAsync();
+
+        return Json(new {
+            lineTotal  = item.TotalPrice,
+            subtotal   = invoice.SubTotal,
+            taxAmount  = invoice.TaxAmount,
+            total      = invoice.Total,
+            balanceDue = invoice.BalanceDue
+        });
+    }
+
     /// <summary>
     /// Returns logo bytes and content type for PDF generation.
     /// Prefers blob-stored logos (LogoFilePath) over the legacy DB column (LogoData).
@@ -3050,3 +3094,11 @@ public class InvoicesController : Controller
         return (company.LogoData, company.LogoContentType);
     }
 }
+
+public class PatchInvoiceItemRequest
+{
+    public int     ItemId      { get; set; }
+    public string  Description { get; set; } = string.Empty;
+    public decimal Quantity    { get; set; }
+    public decimal UnitPrice   { get; set; }
+}