Fix preferred powder search dropdown not appearing

Inline display:none!important on the results div blocked all CSS rules
from showing it, including the :not(:empty) trick. Switched to explicit
JS show/hide so the dropdown is reliably visible after typing 2+ chars.

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

src/PowderCoating.Web/Views/Customers/Details.cshtml

@@ -823,9 +823,8 @@
                                        oninput="searchInventoryItems(this.value)"
                                        autocomplete="off" />
                                 <input type="hidden" id="selectedPowderId" />
-                                <div id="powderSearchResults" class="dropdown-menu w-100 show p-0"
-                                     style="display:none!important;position:absolute;z-index:1000;"
-                                     onfocusout=""></div>
+                                <div id="powderSearchResults" class="dropdown-menu w-100 p-0"
+                                     style="display:none;position:absolute;z-index:1000;max-height:200px;overflow-y:auto;"></div>
                             </div>
                             <div class="mb-2">
                                 <input type="text" id="powderNotes" class="form-control form-control-sm"
@@ -839,9 +838,6 @@
                         </div>
                     </div>
                 </div>
-                <style>
-                    #powderSearchResults:not(:empty) { display:block!important; max-height:200px; overflow-y:auto; }
-                </style>
 
                 <!-- Quick Actions -->
                 <div class="card border-0 shadow-sm">