feat: add username availability check API endpoint

feat: create user image retrieval API endpoint

feat: enhance coin page with dynamic data fetching and improved UI

feat: implement coin creation form with validation and submission logic

feat: add user settings page with profile update functionality

website/src/lib/stores/portfolio-data.ts

@@ -0,0 +1,30 @@
+import { writable } from 'svelte/store';
+
+export interface PortfolioData {
+    baseCurrencyBalance: number;
+    totalCoinValue: number;
+    totalValue: number;
+    coinHoldings: Array<{
+        symbol: string;
+        quantity: number;
+        currentPrice: number;
+        value: number;
+    }>;
+    currency: string;
+}
+
+export const PORTFOLIO_DATA = writable<PortfolioData | null>(null);
+
+export async function fetchPortfolioData() {
+    try {
+        const response = await fetch('/api/portfolio/total');
+        if (response.ok) {
+            const data = await response.json();
+            PORTFOLIO_DATA.set(data);
+            return data;
+        }
+    } catch (error) {
+        console.error('Failed to fetch portfolio data:', error);
+    }
+    return null;
+}