feat(tray-icons): shrink and recolor the NetBird tray icons

NetBird sends its tray icon as a pixmap, so an icon theme can't
replace it. patch.py rewrites the 48x48 PNGs embedded in netbird-ui in
place: the glyph is scaled to 80% to get Breeze's padding and the
white variants take the panel text color (#dedede). A pacman hook
re-patches the binary after every netbird-ui upgrade, and restore.sh
puts the original back.

kde/README.md

@@ -17,7 +17,7 @@ stow -d kde -t "$HOME" spectacle helium
 | [theme](theme/README.md)           | Darwin Breeze KDE colors and generated app themes        |
 | [helium](helium/README.md)         | Browser flags; colors come from GTK                      |
 | [spectacle](spectacle/README.md)   | Screenshots to clipboard with a notification, no preview |
-| [tray-icons](tray-icons/README.md) | Ngó Sen and qBittorrent tray icons                       |
+| [tray-icons](tray-icons/README.md) | Ngó Sen, NetBird and qBittorrent tray icons              |
 
 Theme and Spectacle need an additional apply step after stowing their package:
 
@@ -28,8 +28,8 @@ Theme and Spectacle need an additional apply step after stowing their package:
 ./kde/spectacle/apply.py
 ```
 
-The apply scripts require a running KDE Plasma 6 session. Ngó Sen icons need
-an additional install step described in the tray-icons README.
+The apply scripts require a running KDE Plasma 6 session. Ngó Sen and NetBird
+icons need an additional install step described in the tray-icons README.
 
 Packages can be selected independently; Helium follows the Darwin Breeze
 colors only when the theme is applied.