Add quickshell-git pinned to master e649d24

Quickshell 0.3.0's qs kill returns before the instance exits, which is
what forces omarchy-restart-shell to track pids and wait for death
itself. Master fixed kill to block until the instance is gone (025c709),
so ship our own build pinned at e649d24 until a release catches up.

The #commit= pin plus sync:false keeps upgrades entirely manual: nothing
rebuilds or resyncs until the sha is bumped by hand. Note quickshell
links Qt private APIs, so every Arch qt6 bump needs a pkgrel bump and
rebuild here (the packaged quickshell-check hook warns users if we lag).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

pkgbuilds/quickshell-git/quickshell-check.hook

@@ -0,0 +1,10 @@
+[Trigger]
+Operation = Upgrade
+Operation = Install
+Type = Package
+Target = qt6-base
+Target = qt6-wayland
+[Action]
+Description = Querying Quickshell compatibility after Qt6 update...
+When = PostTransaction
+Exec = /usr/bin/quickshell --private-check-compat