fix: theme KDE Frameworks apps off Plasma

kcalc rendered white under the dark Kvantum theme. Off Plasma,
KStyleManager forces Breeze unless kdeglobals names a widgetStyle, and
KColorSchemeManager applies BreezeLight unless kdeglobals names a colour
scheme; qt6ct never forwards the portal's prefer-dark to Qt.

Generate a udt.colors KColorScheme from the Kvantum roles, install it to
~/.local/share/color-schemes/, and point kdeglobals at it and at
kvantum-dark.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

1 files changed, 11 insertions, 0 deletions

diff --git a/install.sh b/install.sh
index 7b68ad6..8a5755d 100755
--- a/install.sh
+++ b/install.sh
@@ -137,6 +137,17 @@ install -Dm644 "$repo/templates/kvantum/theme.kvconfig" "$kv/udt.kvconfig"
 install -Dm644 "$repo/templates/kvantum/theme.svg"      "$kv/udt.svg"
 printf '[General]\ntheme=udt\n' > "$HOME/.config/Kvantum/kvantum.kvconfig"
 
+# KDE Frameworks apps (kcalc and friends) bypass qt6ct twice over off Plasma:
+# KStyleManager forces Breeze unless kdeglobals names a widgetStyle, and
+# KColorSchemeManager applies BreezeLight unless kdeglobals names a scheme.
+# kdeglobals is edited in place, two keys only, like the gsettings calls below.
+install -Dm644 "$repo/templates/kde/udt.colors" \
+    "$HOME/.local/share/color-schemes/udt.colors"
+if command -v kwriteconfig6 >/dev/null 2>&1; then
+    kwriteconfig6 --file kdeglobals --group UiSettings --key ColorScheme udt
+    kwriteconfig6 --file kdeglobals --group KDE --key widgetStyle kvantum-dark
+fi
+
 # GTK3 and GTK4. Installed under one fixed name for every scheme, like Kvantum:
 # the theme name is set in gsettings and in a symlink, so a per-scheme name
 # would mean rewriting both on every switch and leaving stale themes behind.