Add new animations

Having some animations could make the app feels more alive and fn to use.

Things like:
- buttons visually getting smaller and "popping" after being pressed
- The result sliding into the "main" row
- cursor blinking

If you plan on adding animations:
maybe add a menu option to disable them, or even better have a range slider to choose the speed of the animation:
going from 0 (none) -------- 500ms, with incremental steps (100, 250, 330)

https://user-images.githubusercontent.com/71791731/200374512-5b5773a8-9259-47db-b77d-1eabafc9514b.mp4

No files, tests, or specific entry points are named. Review the Android calculator UI and settings entry point, then compare the current behavior with the linked animation example. Done would require an agreed scope for button, result-row, and cursor animations, plus a decision on whether animation speed or disabling animations is included.

Written by the indexing model from the issue text.