feat(06-03): update display components to use categoryIcon with LucideIcon

- Rename categoryEmoji to categoryIcon in ItemCard, CandidateCard, ThreadCard, ItemPicker
- Import and render LucideIcon at appropriate sizes (36px placeholder, 14-16px badges)
- Update hook interfaces to match server API (categoryIcon instead of categoryEmoji)
- Rename iconData.ts to iconData.tsx (contains JSX)
- Update useCategories mutation type to use icon instead of emoji

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/client/components/ItemPicker.tsx

@@ -3,6 +3,7 @@ import { SlideOutPanel } from "./SlideOutPanel";
 import { useItems } from "../hooks/useItems";
 import { useSyncSetupItems } from "../hooks/useSetups";
 import { formatWeight, formatPrice } from "../lib/formatters";
+import { LucideIcon } from "../lib/iconData";
 
 interface ItemPickerProps {
   setupId: number;
@@ -51,7 +52,7 @@ export function ItemPicker({
     number,
     {
       categoryName: string;
-      categoryEmoji: string;
+      categoryIcon: string;
       items: NonNullable<typeof items>;
     }
   >();
@@ -64,7 +65,7 @@ export function ItemPicker({
       } else {
         grouped.set(item.categoryId, {
           categoryName: item.categoryName,
-          categoryEmoji: item.categoryEmoji,
+          categoryIcon: item.categoryIcon,
           items: [item],
         });
       }
@@ -83,10 +84,10 @@ export function ItemPicker({
             </div>
           ) : (
             Array.from(grouped.entries()).map(
-              ([categoryId, { categoryName, categoryEmoji, items: catItems }]) => (
+              ([categoryId, { categoryName, categoryIcon, items: catItems }]) => (
                 <div key={categoryId} className="mb-4">
                   <h3 className="text-xs font-semibold text-gray-500 uppercase tracking-wider mb-2">
-                    {categoryEmoji} {categoryName}
+                    <LucideIcon name={categoryIcon} size={16} className="inline-block mr-1 text-gray-500" /> {categoryName}
                   </h3>
                   <div className="space-y-1">
                     {catItems.map((item) => (