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

lib/supabase.ts

@@ -4,8 +4,3 @@ const supabaseUrl = process.env.NEXT_PUBLIC_SUPABASE_URL!;
 const supabaseAnonKey = process.env.NEXT_PUBLIC_SUPABASE_ANON_KEY!;
 
 export const supabase = createClient(supabaseUrl, supabaseAnonKey);
-
-export const supabaseAdmin = createClient(
-    supabaseUrl,
-    process.env.SUPABASE_SERVICE_ROLE_KEY!
-);