feat: implement hierarchical category management with parent-child relationships and enhance category creation dialog

app/statistics/page.tsx

@@ -6,6 +6,7 @@ import { useBankingData } from "@/lib/hooks"
 import { Card, CardContent, CardHeader, CardTitle } from "@/components/ui/card"
 import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from "@/components/ui/select"
 import { RefreshCw, TrendingUp, TrendingDown, ArrowRight } from "lucide-react"
+import { CategoryIcon } from "@/components/ui/category-icon"
 import {
   BarChart,
   Bar,
@@ -385,9 +386,10 @@ export default function StatisticsPage() {
                               </span>
                               {category && (
                                 <span
-                                  className="text-xs px-1.5 py-0.5 rounded"
+                                  className="text-xs px-1.5 py-0.5 rounded inline-flex items-center gap-1"
                                   style={{ backgroundColor: `${category.color}20`, color: category.color }}
                                 >
+                                  <CategoryIcon icon={category.icon} color={category.color} size={10} />
                                   {category.name}
                                 </span>
                               )}