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/TransactionSearch.tsx

@@ -0,0 +1,41 @@
+'use client';
+
+import React, { useState, useEffect } from 'react';
+import { useRouter, useSearchParams } from 'next/navigation';
+import { Search } from 'lucide-react';
+
+export default function TransactionSearch() {
+    const router = useRouter();
+    const searchParams = useSearchParams();
+    const [searchTerm, setSearchTerm] = useState(searchParams.get('q') || '');
+
+    useEffect(() => {
+        const currentQ = searchParams.get('q') || '';
+        if (searchTerm === currentQ) return;
+
+        const delayDebounceFn = setTimeout(() => {
+            const params = new URLSearchParams(searchParams.toString());
+            if (searchTerm) {
+                params.set('q', searchTerm);
+            } else {
+                params.delete('q');
+            }
+            router.push(`/admin/transactions?${params.toString()}`);
+        }, 500);
+
+        return () => clearTimeout(delayDebounceFn);
+    }, [searchTerm, searchParams, router]);
+
+    return (
+        <div className="relative flex-1 max-w-md">
+            <Search className="absolute left-4 top-1/2 -translate-y-1/2 text-gray-400" size={20} />
+            <input
+                type="text"
+                placeholder="İşlem ID veya referans ile ara..."
+                value={searchTerm}
+                onChange={(e) => setSearchTerm(e.target.value)}
+                className="w-full pl-12 pr-6 py-3 bg-gray-50 border-none rounded-2xl text-sm font-medium focus:ring-2 focus:ring-blue-500 outline-none placeholder:text-gray-300"
+            />
+        </div>
+    );
+}