feat: add Solana USDT/USDC support and refine admin payouts UI

app/api/admin/payouts/list/route.ts

@@ -0,0 +1,23 @@
+import { NextRequest, NextResponse } from 'next/server';
+import { db } from '@/lib/db';
+
+export async function GET(req: NextRequest) {
+    try {
+        const result = await db.query(`
+            SELECT 
+                p.*,
+                m.name as merchant_name
+            FROM payouts p
+            LEFT JOIN merchants m ON p.merchant_id = m.id
+            ORDER BY p.created_at DESC
+        `);
+
+        return NextResponse.json({
+            success: true,
+            payouts: result.rows
+        });
+    } catch (error: any) {
+        console.error('[Payouts List API] Error:', error);
+        return NextResponse.json({ error: error.message }, { status: 500 });
+    }
+}