Move cua-driver-bin off the fast ring and keep its bumps manual (#692)

Build it in edge and promote through rc to stable like other packages,
matching cua-hyprland-plugin, which left the fast ring in #432.

#693 held upstream sync while 0.28.3+ breaks screenshots. Make that the
standing policy: Omarchy bumps the driver by hand, so the PKGBUILD no
longer says to re-enable sync after the fix, and docs/upstream-sources.md
records the hold. The hook and min_release_age stay, so lifting the hold
is a one-line revert.

Publish as 0.28.2-3 so the PR builds; the payload is unchanged.

pkgbuilds/cua-driver-bin/.omarchy/package.json

@@ -1,6 +1,5 @@
 {
   "source": "local",
   "sync": false,
-  "release_ring": "fast",
   "min_release_age": "24h"
 }