feat(darwin-breeze): unify theme colors across KDE, Helium, T3 Code and Ghostty

Move the Darwin Breeze Dark color scheme and global theme into a stow
package. build.py generates the Helium, T3 Code and Ghostty themes from
DarwinBreezeDark.colors, and apply.sh rebuilds and applies them, so the
colors are edited in one place.

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

helium/.config/helium-browser-flags.conf

@@ -0,0 +1,6 @@
+# Hardware video acceleration (VA-API, AMD radeonsi) on Wayland
+--ozone-platform-hint=auto
+--enable-features=AcceleratedVideoDecodeLinuxGL,AcceleratedVideoDecodeLinuxZeroCopyGL,AcceleratedVideoEncoder
+
+# Darwin Breeze theme, generated by darwin-breeze/build.py
+--load-extension=~/.local/share/helium-themes/darwinbreeze