gamma: reset lastAppliedTemp on suspend instead of destroying/recreating

outputs

fixes #2199 , possibly regresses #1235 - but I think the original bug
was lastAppliedTemp being incorrectly set, this allows compositors to
cache last applied gamma

gamma: add a bunch of defensive mechanisms for output changes
related to #2197

gamma: ensure gamma is re-evaluate on resume
fixes #1036

quickshell/Services/DisplayService.qml

@@ -819,6 +819,7 @@ Singleton {
             if (event.event === "unlock" || event.event === "resume") {
                 suppressOsd = true;
                 osdSuppressTimer.restart();
+                evaluateNightMode();
             }
         }