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/Views/Quotes/Details.cshtml

@@ -80,12 +80,24 @@
                         else
                         {
                             <div class="col-md-12">
-                                <p>
-                                    <strong>Customer:</strong>
-                                    <a asp-controller="Customers" asp-action="Details" asp-route-id="@Model.CustomerId">
-                                        @Model.CustomerName
-                                    </a>
-                                </p>
+                                @Html.AntiForgeryToken()
+                                <strong>Customer:</strong>
+                                <div data-cc-wrap data-cc-id="@Model.Id"
+                                     data-cc-url="@Url.Action("ChangeCustomer", "Quotes")"
+                                     class="d-inline-block ms-1">
+                                    <select class="form-select form-select-sm cc-select" style="max-width:300px;">
+                                        @foreach (var c in (IEnumerable<Microsoft.AspNetCore.Mvc.Rendering.SelectListItem>)ViewBag.CustomerSelectList)
+                                        {
+                                            <option value="@c.Value" selected="@(c.Value == Model.CustomerId.ToString() ? "selected" : null)">@c.Text</option>
+                                        }
+                                    </select>
+                                    <div class="cc-confirm-banner d-none mt-2 p-2 bg-light border rounded d-flex align-items-center gap-2 flex-wrap">
+                                        <span class="cc-confirm-text small fw-semibold"></span>
+                                        <button type="button" class="btn btn-success btn-sm" data-cc-save>Save</button>
+                                        <button type="button" class="btn btn-outline-secondary btn-sm" data-cc-cancel>Cancel</button>
+                                    </div>
+                                    <div class="cc-error text-danger small mt-1 d-none"></div>
+                                </div>
                             </div>
                         }
                     </div>
@@ -2030,6 +2042,7 @@
 </div>
 
 @section Scripts {
+    <script src="~/js/customer-change.js" asp-append-version="true"></script>
     <script>
         function resendQuote(quoteId) {
             // Reset modal state