fix: blurry splash screen icon

[jvsena42]

This PR:

1. Fixes the splash screen icon appearing deformed/stretched by making the vector drawable square (200x200 instead of 200x184)
2. Adds a dedicated splash_logo_icon drawable wrapper with insets to properly size the icon within the circular splash mask
3. Removes 18 unused mipmap resources (ic_launcher_transparent, ic_launcher_black, ic_launcher_black_round)

Description

The splash screen was using ic_launcher_foreground directly, which has a non-square viewport (200x184dp). Android 12+ renders splash icons into a square container, stretching the icon vertically and making it look thin. The fix squares the viewport and centers the content with a translate group. A wrapper drawable (splash_logo_icon.xml) adds 23% insets to fit the icon within the circular mask area.

Preview

pixel-6.webm

medium-phone.webm

small_phone.webm

QA Notes

1. Launch the app and observe the splash screen
2. Verify the Bitkit icon appears correctly proportioned (not stretched or squished)
3. Verify the icon fits within the circular splash area without clipping
4. Verify the app launcher icon still renders correctly on the home screen

[jvsena42]

I could also remove the compose splash screen and keep only the system one, but the "BITKIT" icon can't fit in the required size, I would have to make it smaller