feat(icons): shrink the Android adaptive mark 25%, give old square launchers the full-bleed master

The adaptive foreground's asterisk grazed the round mask's safe zone. Scale the
foreground mark 0.75 about the icon centre (25% smaller, the letter-to-star
arrangement unchanged) so it sits well inside the 61% safe zone. Independently,
the legacy square ic_launcher.png now renders the full-bleed master instead of
the safe-zone composite, so old Android (< API 26) shows a large mark rather
than a shrunk one; the legacy round icon keeps the safe-zone composite (a round
mask would clip the master's corner star). Regenerate the layer set, Android
res and the brandbook foreground previews; update ICON_BRANDBOOK.md / ICONS.md.

docs/ICONS.md

@@ -54,7 +54,10 @@ already fill the 108 dp canvas (foreground inside the 61 % safe zone, background
 full-bleed), so they must be placed with **no inset**, and we add the **monochrome**
 themed layer, neither of which `capacitor-assets` does. Per density mdpi→xxxhdpi (+ldpi):
 
-- `mipmap-*/ic_launcher.png` / `ic_launcher_round.png` — legacy square / round (composite)
+- `mipmap-*/ic_launcher.png` — legacy square (< API 26): the **full-bleed master** (large
+  mark), so old square launchers do not shrink it into the safe zone
+- `mipmap-*/ic_launcher_round.png` — legacy round (< API 26): the safe-zone **composite**,
+  circle-clipped (a round mask would clip the master's corner ✻)
 - `mipmap-*/ic_launcher_foreground.png` + `ic_launcher_background.png` — adaptive layers
 - `mipmap-*/ic_launcher_monochrome.png` — themed layer
 - `mipmap-anydpi-v26/ic_launcher.xml` + `ic_launcher_round.xml` — **no `<inset>`**, with