feat: implement merchant dashboard, secure auth, and short_id system

- Added dedicated merchant dashboard with analytics and transactions
- Implemented API Key based authentication for merchants
- Introduced 8-character Short IDs for merchants to use in URLs
- Refactored checkout and payment intent APIs to support multi-gateway
- Enhanced Landing Page with Merchant Portal access and marketing copy
- Fixed Next.js 15 async params build issues
- Updated internal branding to P2CGateway
- Added AyrisTech credits to footer

components/admin/TransactionStatusFilter.tsx

@@ -0,0 +1,40 @@
+'use client';
+
+import React from 'react';
+import { useRouter, useSearchParams } from 'next/navigation';
+import { Filter } from 'lucide-react';
+
+export default function TransactionStatusFilter() {
+    const router = useRouter();
+    const searchParams = useSearchParams();
+    const currentStatus = searchParams.get('status') || '';
+
+    const handleStatusChange = (e: React.ChangeEvent<HTMLSelectElement>) => {
+        const value = e.target.value;
+        if (value === currentStatus) return;
+
+        const params = new URLSearchParams(searchParams.toString());
+        if (value) {
+            params.set('status', value);
+        } else {
+            params.delete('status');
+        }
+        router.push(`/admin/transactions?${params.toString()}`);
+    };
+
+    return (
+        <div className="flex items-center gap-2 px-4 py-3 bg-white border border-gray-100 rounded-2xl">
+            <Filter size={18} className="text-gray-400" />
+            <select
+                value={currentStatus}
+                onChange={handleStatusChange}
+                className="bg-transparent border-none text-sm font-bold text-gray-600 outline-none cursor-pointer"
+            >
+                <option value="">Tüm Durumlar</option>
+                <option value="succeeded">Başarılı</option>
+                <option value="pending">Bekliyor</option>
+                <option value="failed">Hatalı</option>
+            </select>
+        </div>
+    );
+}