Add dropper location selector: discover available droppers on network, pass through server, and add dropdown in order panel for location-based dispensing

web/client/src/components/InventoryGrid.css

@@ -412,6 +412,51 @@
   flex-wrap: wrap;
 }
 
+/* Dropper location selector */
+.dropper-select-wrapper {
+  display: flex;
+  flex-direction: column;
+  gap: 0.25rem;
+}
+
+.dropper-label {
+  font-size: 0.65rem;
+  color: var(--mc-text-gold);
+  text-shadow: 1px 1px 0 #000;
+}
+
+.dropper-select {
+  background: #2a2a2a;
+  border: 2px solid #444;
+  color: var(--mc-text-white);
+  font-family: 'Silkscreen', 'Courier New', monospace;
+  font-size: 0.7rem;
+  padding: 0.375rem 0.5rem;
+  outline: none;
+  border-radius: 0;
+  cursor: pointer;
+  appearance: none;
+  -webkit-appearance: none;
+  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='10' height='6'%3E%3Cpath d='M0 0l5 6 5-6z' fill='%23aaa'/%3E%3C/svg%3E");
+  background-repeat: no-repeat;
+  background-position: right 0.5rem center;
+  padding-right: 1.5rem;
+}
+
+.dropper-select:hover {
+  border-color: var(--mc-text-green);
+}
+
+.dropper-select:focus {
+  border-color: var(--mc-text-green);
+  box-shadow: inset 0 0 4px rgba(85, 255, 85, 0.15);
+}
+
+.dropper-select option {
+  background: #1a1a1a;
+  color: var(--mc-text-white);
+}
+
 .order-btn {
   width: 100%;
   padding: 0.625rem !important;