Add AI Quick Quote widget and inline customer reassignment

- New AI Quick Quote floating button: staff type a verbal description to
  get an instant price estimate for phone/walk-in customers; detected
  color names are fuzzy-matched against inventory for stock status;
  saves draft quote under a Walk-In / Phone customer with one click
- Inline customer change on Quote Details and Job Details: always-visible
  native select with inline confirmation banner (no TomSelect dependency);
  ChangeCustomer AJAX endpoints on QuotesController and JobsController
- Quote Edit page: customer dropdown is now editable (lock removed)
- Fix AutoMapper missing CatalogCategory -> UpdateCategoryDto mapping
  that caused a crash on the catalog category Edit page
- Help docs and AI knowledge base updated for all three features

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

src/PowderCoating.Web/Controllers/JobsController.cs

@@ -521,6 +521,20 @@ public class JobsController : Controller
             ViewBag.JobPhotoUsed = photoUsed;
             ViewBag.JobPhotoMax = photoMax;
 
+            // Customer list for inline customer-change dropdown
+            var allCustomers = await _unitOfWork.Customers.GetAllAsync();
+            ViewBag.CustomerSelectList = allCustomers
+                .Where(c => c.IsActive)
+                .Select(c => new SelectListItem
+                {
+                    Value = c.Id.ToString(),
+                    Text = !string.IsNullOrWhiteSpace(c.CompanyName)
+                        ? c.CompanyName
+                        : $"{c.ContactFirstName} {c.ContactLastName}".Trim()
+                })
+                .OrderBy(c => c.Text)
+                .ToList();
+
             return View(jobDto);
         }
         catch (Exception ex)
@@ -531,6 +545,30 @@ public class JobsController : Controller
         }
     }
 
+    /// <summary>
+    /// Reassigns a job to a different customer.
+    /// </summary>
+    [HttpPost]
+    [ValidateAntiForgeryToken]
+    public async Task<IActionResult> ChangeCustomer(int id, int customerId)
+    {
+        var job = await _unitOfWork.Jobs.GetByIdAsync(id);
+        if (job == null) return NotFound();
+
+        var customer = await _unitOfWork.Customers.GetByIdAsync(customerId);
+        if (customer == null)
+            return Json(new { success = false, error = "Customer not found." });
+
+        job.CustomerId = customerId;
+        await _unitOfWork.CompleteAsync();
+
+        var customerName = !string.IsNullOrWhiteSpace(customer.CompanyName)
+            ? customer.CompanyName
+            : $"{customer.ContactFirstName} {customer.ContactLastName}".Trim();
+
+        return Json(new { success = true, customerName, customerId = customer.Id });
+    }
+
     // ── Shop Floor QR Status Bump ────────────────────────────────────────────
 
     /// <summary>