TextStamp v0.1.0

feat: Add adaptive launcher icons and Play Store icon

This commit introduces a complete set of launcher icons for the application.

Specifically, the following assets have been added:
*   Adaptive launcher icons (`ic_launcher.xml` and `ic_launcher_round.xml`) for Android 8.0 (API 26) and above.
*   WebP assets for the adaptive icon's background and foreground layers across all standard density buckets (mdpi, hdpi, xhdpi, xxhdpi, xxxhdpi).
*   A high-resolution PNG icon (`ic_launcher-playstore.png`) for use in the Google Play Store listing.