feat(06-02): replace EmojiPicker with IconPicker across all category components

- CategoryPicker shows LucideIcon prefix and uses IconPicker for inline create
- CategoryHeader displays LucideIcon in view mode and IconPicker in edit mode
- OnboardingWizard uses IconPicker for category creation step
- CreateThreadModal drops emoji from category select options
- Fixed categoryEmoji -> categoryIcon in routes and useCategories hook

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

src/client/routes/collection/index.tsx

@@ -98,7 +98,7 @@ function CollectionView() {
 	// Group items by categoryId
 	const groupedItems = new Map<
 		number,
-		{ items: typeof items; categoryName: string; categoryEmoji: string }
+		{ items: typeof items; categoryName: string; categoryIcon: string }
 	>();
 
 	for (const item of items) {
@@ -109,7 +109,7 @@ function CollectionView() {
 			groupedItems.set(item.categoryId, {
 				items: [item],
 				categoryName: item.categoryName,
-				categoryEmoji: item.categoryEmoji,
+				categoryIcon: item.categoryIcon,
 			});
 		}
 	}
@@ -134,7 +134,7 @@ function CollectionView() {
 			{Array.from(groupedItems.entries()).map(
 				([
 					categoryId,
-					{ items: categoryItems, categoryName, categoryEmoji },
+					{ items: categoryItems, categoryName, categoryIcon },
 				]) => {
 					const catTotals = categoryTotalsMap.get(categoryId);
 					return (
@@ -142,7 +142,7 @@ function CollectionView() {
 							<CategoryHeader
 								categoryId={categoryId}
 								name={categoryName}
-								emoji={categoryEmoji}
+								icon={categoryIcon}
 								totalWeight={catTotals?.totalWeight ?? 0}
 								totalCost={catTotals?.totalCost ?? 0}
 								itemCount={catTotals?.itemCount ?? categoryItems.length}
@@ -156,7 +156,7 @@ function CollectionView() {
 										weightGrams={item.weightGrams}
 										priceCents={item.priceCents}
 										categoryName={categoryName}
-										categoryEmoji={categoryEmoji}
+										categoryIcon={categoryIcon}
 										imageFilename={item.imageFilename}
 									/>
 								))}
@@ -268,7 +268,7 @@ function PlanningView() {
 					<option value="">All categories</option>
 					{categories?.map((cat) => (
 						<option key={cat.id} value={cat.id}>
-							{cat.emoji} {cat.name}
+							{cat.name}
 						</option>
 					))}
 				</select>
@@ -356,7 +356,7 @@ function PlanningView() {
 							createdAt={thread.createdAt}
 							status={thread.status}
 							categoryName={thread.categoryName}
-							categoryEmoji={thread.categoryEmoji}
+							categoryIcon={thread.categoryIcon}
 						/>
 					))}
 				</div>