Looking migrate to next js and integrate sanity

Please note the following I work only via Upwork, I will not hire anyone outside of the platform and neither I will reply to any messages outside of it. I am looking for an experienced developer to help improve and optimize my existing puzzle gaming platform, Puzzroo.com The current platform is built with React, Vite and TypeScript. I would like to migrate it to Next.js App Router and integrate Sanity CMS to improve SEO, content management and scalability. The project includes: - Migrating the existing React application to Next.js App Router. - Preserving the existing four puzzle games, admin panel and leaderboard functionality. - Integrating Sanity CMS for game pages, blog content, FAQs and SEO metadata. - Implementing technical SEO best practices, including metadata, structured data, sitemap, robots.txt and appropriate URL structures. - Ensuring the platform works correctly, remains responsive and is ready for production. - Testing the migration and fixing any issues before delivery. AI-assisted development An important requirement is to use AI tools extensively throughout the development process to reduce development time and costs without compromising code quality, security, performance or reliability. I am not looking for someone who simply generates code using AI without proper validation. I need a developer who understands the architecture, can manage integrations, debug problems, test the implementation and ensure the final product is production-ready. Please explain how you would use AI to accelerate the work, which tasks can be completed efficiently with AI, and where your engineering expertise and manual testing would be required. Proposal requirements Please provide a fixed-price quote broken down into milestones, with estimated timelines, deliverables, testing procedures and any exclusions or potential additional costs. Please also explain how you calculate the estimated development time and cost, and how you would ensure that AI-assisted development genuinely reduces the total cost without compromising quality. As a separate item, please provide an optional quote for implementing localization across approximately 20–25 languages. I am open to starting with a small, paid proof of concept to evaluate your approach before committing to the full project. I will provide access to the existing codebase and relevant systems once we agree on the scope.