Add packing slip PDF to invoice details page

Generates a no-price packing slip (items, color, qty + signature line) via
QuestPDF. New DownloadPackingSlip action reuses existing invoice data pipeline;
Packing Slip button opens inline in a new tab same as Print/PDF.

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

src/PowderCoating.Web/Controllers/InvoicesController.cs

@@ -1782,6 +1782,59 @@ public class InvoicesController : Controller
         }
     }
 
+    // -----------------------------------------------------------------------
+    // GET: /Invoices/DownloadPackingSlip/5
+    // -----------------------------------------------------------------------
+    /// <summary>
+    /// Generates a no-price packing slip PDF for physical pickup/delivery paperwork.
+    /// Reuses the same company branding and invoice data pipeline as DownloadPdf but
+    /// delegates to GeneratePackingSlipPdfAsync which omits all pricing columns.
+    /// </summary>
+    public async Task<IActionResult> DownloadPackingSlip(int? id, bool inline = false)
+    {
+        if (id == null) return NotFound();
+
+        try
+        {
+            var invoice = await LoadInvoiceForViewAsync(id.Value);
+            if (invoice == null) return NotFound();
+
+            var currentUser = await _userManager.GetUserAsync(User);
+            if (currentUser == null) return Unauthorized();
+
+            var company = await _unitOfWork.Companies.GetByIdAsync(currentUser.CompanyId);
+            var companyInfo = new Application.DTOs.Company.CompanyInfoDto
+            {
+                CompanyName = company?.CompanyName ?? string.Empty,
+                Phone = company?.Phone,
+                Address = company?.Address,
+                City = company?.City,
+                State = company?.State,
+                ZipCode = company?.ZipCode,
+                PrimaryContactEmail = company?.PrimaryContactEmail
+            };
+
+            var (logoData, logoContentType) = await LoadCompanyLogoAsync(company);
+            var dto = await BuildInvoiceDtoAsync(invoice);
+            var pdfBytes = await _pdfService.GeneratePackingSlipPdfAsync(dto, logoData, logoContentType, companyInfo);
+            var fileName = $"PackingSlip-{invoice.InvoiceNumber}.pdf";
+
+            if (inline)
+            {
+                Response.Headers["Content-Disposition"] = $"inline; filename=\"{fileName}\"";
+                return File(pdfBytes, "application/pdf");
+            }
+
+            return File(pdfBytes, "application/pdf", fileName);
+        }
+        catch (Exception ex)
+        {
+            _logger.LogError(ex, "Error generating packing slip for invoice {Id}", id);
+            TempData["ErrorPermanent"] = $"Packing slip generation failed: {ex.Message}";
+            return RedirectToAction(nameof(Details), new { id });
+        }
+    }
+
     // -----------------------------------------------------------------------
     // GET: /Invoices/ForJob/5  — redirect to existing or Create
     // -----------------------------------------------------------------------