docs: mark plymouth contrast done; log GTK/Qt light-dark issue

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

README.md

@@ -341,10 +341,12 @@ close · `SUPER+1..9` workspaces · `Print` region screenshot.
   `nomarchy.apps.*` option surface so each is individually opt-out for
   users who want a leaner machine. Watch closure size (texlive-full is
   multi-GB — likely default-off or a lighter scheme).
-- **Plymouth logo contrast:** the shipped splash logo is too dark against
-  the dark `base` background; recolor/lighten it (or tint from the palette
-  `accent`/`text` instead of shipping a fixed navy asset) so it reads on
-  both light and dark themes.
+- ✓ **Plymouth logo contrast:** the shipped art was a fixed navy that
+  vanished on dark bases. `modules/nixos/plymouth.nix` now recolors every
+  element from the palette at build time (flat fill, alpha kept):
+  logo/lock/bullet → text, entry/progress-box → surface, progress-bar →
+  accent. Reads on light and dark; follows the theme as of the last system
+  rebuild (like the background tint).
 - **Hibernate double-unlock:** on resume from hibernate the LUKS
   passphrase already gates the machine, but hypridle's `before_sleep_cmd`
   also locks hyprlock, so the user types a password twice. Lock only on
@@ -395,3 +397,11 @@ close · `SUPER+1..9` workspaces · `Print` region screenshot.
   Waybar honours → all 10 rendered as phantoms. Dropped the block from
   `themes/summer-{day,night}/waybar.jsonc`; the other themes use the
   generated `waybar.nix`, which never had it, so they already match.
+- **GTK/Qt ignore the theme's light/dark mode:** `stylix.nix` sets
+  `polarity` from `theme.mode`, but GTK4/libadwaita apps (and Qt via the
+  portal) decide dark vs light from the `org.freedesktop.appearance
+  color-scheme` / gsettings `org.gnome.desktop.interface color-scheme` key,
+  which Stylix doesn't write — so a light theme can still render apps dark
+  (and vice-versa). Fix: set `dconf` `color-scheme` =
+  `prefer-dark`/`prefer-light` from `t.mode` (and confirm the
+  xdg-desktop-portal exposes it), so libadwaita/Qt follow the palette.