Root cause: TWA LauncherActivity.onCreate calls Bitmap.createBitmap on the
splash drawable — the XML layer-list with only a color fill had 0x0 intrinsic
dimensions, causing IllegalArgumentException: "width and height must be > 0".
Fixes:
- Replace splash.xml with splash.png (384x384 blue circle with P logo)
- Add proper PNG launcher icons at all 5 density buckets (mdpi through xxxhdpi)
- Change android:icon from @drawable to @mipmap for proper icon resolution
