Welcome-screen branding pass to match the new launcher icon:
- Logo: swap ic_wisp_logo + the drawn radial-gradient disc for the
dark-wisp round mark on a solid black circle, delivered via a raster
drawable (ic_brand_logo). The mipmap can't be used directly because
R.mipmap.ic_launcher_round resolves to the adaptive-icon XML on
API 26+, which Compose's painterResource cannot render.
- Wordmark: restyle "dark wisp" from flat white to black text ringed in
an orange glow (brand orange #FF9800).
- Cancel (add-account flow): move out from under the logo/buttons
column, where it was painted over, to a visible pill in the top-start
corner (mirroring the Tor button at top-end).