I already have the complete Flutter codebase in hand and need it transformed into a fully working cross-platform application. Your task is to set up the project, resolve any build-time issues that may appear, and generate release-ready builds for both Android (APK/AAB) and iOS (IPA). The code should compile without warnings, run smoothly on current OS versions, and mirror the behaviour shown in the existing source. If minor configuration tweaks—such as bundle IDs, signing, or store assets—are required, please handle them and document the changes so I can maintain the project later. Deliverables • Clean, reproducible build of the Flutter project • Signed Android APK/AAB and iOS IPA (TestFlight-ready) • A brief read-me outlining build steps, environment versions, and any adjustments you made If you can also guide me through submitting to Google Play and the App Store, let me know—this would be a welcome plus.