make the app fully responsive, irrespective of the device size

`responsive_framework` from pub.dev can be integrated to make the app fully responsive for all the devices.

The issue suggests integrating the 'responsive_framework' package from pub.dev. Start by examining the existing Flutter UI structure to understand layout patterns. Research the package's documentation and examples to see how it adapts widgets to different screen sizes. Implement the framework across key screens, then test on various device simulators to ensure responsiveness.

索引モデルが issue の本文から書いたものです。