feat: add CoinIcon component for displaying cryptocurrency icons

feat: implement TradeModal for buying and selling coins with validation and transaction handling

feat: create server-side trade API for executing buy/sell transactions and updating user balances

feat: add transactions API to fetch user transaction history

feat: implement portfolio page to display user's holdings and recent transactions

website/src/routes/api/transactions/+server.ts

@@ -0,0 +1,51 @@
+import { auth } from '$lib/auth';
+import { error, json } from '@sveltejs/kit';
+import { db } from '$lib/server/db';
+import { transaction, coin } from '$lib/server/db/schema';
+import { eq, desc } from 'drizzle-orm';
+
+export async function GET({ request }) {
+    const session = await auth.api.getSession({
+        headers: request.headers
+    });
+
+    if (!session?.user) {
+        throw error(401, 'Not authenticated');
+    }
+
+    const userId = Number(session.user.id);
+
+    const transactions = await db
+        .select({
+            id: transaction.id,
+            type: transaction.type,
+            quantity: transaction.quantity,
+            pricePerCoin: transaction.pricePerCoin,
+            totalBaseCurrencyAmount: transaction.totalBaseCurrencyAmount,
+            timestamp: transaction.timestamp,
+            coinSymbol: coin.symbol,
+            coinName: coin.name,
+            coinIcon: coin.icon
+        })
+        .from(transaction)
+        .innerJoin(coin, eq(transaction.coinId, coin.id))
+        .where(eq(transaction.userId, userId))
+        .orderBy(desc(transaction.timestamp))
+        .limit(100);
+
+    return json({
+        transactions: transactions.map(t => ({
+            id: t.id,
+            type: t.type,
+            quantity: Number(t.quantity),
+            pricePerCoin: Number(t.pricePerCoin),
+            totalBaseCurrencyAmount: Number(t.totalBaseCurrencyAmount),
+            timestamp: t.timestamp,
+            coin: {
+                symbol: t.coinSymbol,
+                name: t.coinName,
+                icon: t.coinIcon
+            }
+        }))
+    });
+}