feat: introduce customizable background options with new gradient and solid color styles; integrate BackgroundProvider and BackgroundCard components for enhanced user experience in settings and layout

app/settings/page.tsx

@@ -9,6 +9,7 @@ import {
   BackupCard,
   PasswordCard,
   ReconcileDateRangeCard,
+  BackgroundCard,
 } from "@/components/settings";
 import { useBankingData } from "@/lib/hooks";
 import type { BankingData } from "@/lib/types";
@@ -126,6 +127,8 @@ export default function SettingsPage() {
 
         <PasswordCard />
 
+        <BackgroundCard />
+
         <ReconcileDateRangeCard />
 
         <DangerZoneCard