feat(frontend): enhance trading item search and keyboard navigation

Implement weighted search scoring for trading items
Add keyboard support (arrows, enter) for item selection
Limit trading detail list height with independent scrolling

frontend/src/styles/main.css

@@ -5143,6 +5143,14 @@ button:disabled,
   flex-wrap: wrap;
 }
 
+.trading-detail-list {
+  max-height: 360px;
+  overflow: auto;
+  padding-right: 4px;
+  overscroll-behavior: contain;
+  scrollbar-gutter: stable;
+}
+
 .trading-manager {
   min-height: 640px;
   display: grid;
@@ -5232,6 +5240,11 @@ button:disabled,
   background: var(--surface-soft);
 }
 
+.trading-pick-row--active {
+  border-color: var(--pokemon-blue);
+  box-shadow: 0 0 0 2px rgba(42, 117, 187, .16);
+}
+
 .trading-pick-row__copy,
 .trading-selected-list__copy {
   min-width: 0;
@@ -5320,6 +5333,10 @@ button:disabled,
     max-height: 240px;
   }
 
+  .trading-detail-list {
+    max-height: 280px;
+  }
+
   .trading-preference-toggle,
   .trading-selected-list .plain-button--icon {
     grid-column: 2;