Lead Full-Stack Developer (Flutter & Node.js) for Premium App

I am looking for an expert Lead Full-Stack Developer to build a premium interactive mobile app (iOS & Android) along with a secure and comprehensive admin dashboard. Project Overview: It is a premium digital collectible card application for iOS and Android. It is not a combat or stats-based game; it is purely focused on high-quality art, story (lore), and collecting unique items. Specifically, the artwork on these digital cards will be high-resolution images of real, luxurious physical paintings. Core Features and Mechanics: - Interactive 3D Cards: The cards have a 2:3 ratio. The front features the image of the real luxurious painting (with a slight 3D pop-out effect), name, serial number, and rarity. When the user taps the card, it performs a smooth 3D flip animation to reveal the back, which displays a personalized "daily cosmic message." - Closed Economy System: The app uses an internal currency called Tokens (1 Token = $1). Tokens are purchased exclusively through Apple Pay and Google Pay (In-App Purchases). Users cannot withdraw Tokens for real money, complying with app store policies. - Store and Purchasing: Users can buy "Blind Boxes" (mystery packs) or specific cards directly from the main store. - The Museum: A personal digital gallery (dashboard/UI) where each user can elegantly display their collected cards and albums. - Secondary Marketplace: A trading system where users can buy, sell, or bid on cards among themselves using Tokens. The backend system needs to automatically deduct a 3% to 5% commission (token burn) on every sale. - External Verification: A simple public webpage linked to a barcode or serial number on the digital card to prove its authenticity, original owner, and current ownership chain. Key Technical Requirements: - Frontend: Strong experience in Flutter, specifically implementing smooth 3D animations (e.g., high-quality 3D card flip effects). - Backend: Expertise in Node.js and PostgreSQL to build a secure architecture. - Payments: Proven experience integrating native In-App Purchases (Apple Pay & Google Pay). - Dashboard: Building a user-friendly Admin Panel to manage users, items, and sales. Important Note: The commercial concept and project details are strictly confidential. The selected developer will be required to sign a Non-Disclosure Agreement (NDA) before any UI/UX designs or full project scope are shared. Please apply only if you have solid proof of the required skills in your portfolio.