gamma goes to the compositor, not to a binary that is not there

hyprsunset does not exist under viewtop and execDetached cannot fail loudly,
so the brightness slider and the night light have done nothing since the
move. Same public surface, pointed at viewtop's gamma verb. TASK-61.

Keeps the upstream name: every consumer in the tree spells it, and renaming
across the base tree and the phone overlay is its own sweep.

import Quickshell was missing, which made the Singleton type unavailable and
failed the whole qs.services module — 29 singletons, 28 had it. The phone's
shell was in a restart loop with a 26-line cascade whose only real line was
the last one.

surfaces/quickshell/services/Hyprsunset.qml

@@ -25,6 +25,7 @@
 // is trap #5 in START-HERE, and it has cost this project three sessions.
 pragma Singleton
 
+import Quickshell
 import QtQuick
 import qs.modules.common