ci: Github Actions file cache

## Description
To detekt lint check and app build check took 6 min. (wtf?)
We need to cache the file. (i.e. gradle, android sdk)

## Screenshots

<img width="490" height="164" alt="Image" src="https://github.com/user-attachments/assets/2acd51c1-d092-443c-8f75-ea1aeb54b64f" />