Sync LightSwitch event names, add monitor refresh delay

- Use shared constants for LightSwitch theme event names in both C++ and C# to ensure cross-module consistency.
- Replace "Brightness update rate" with "Monitor refresh delay" setting in PowerDisplay; user can now configure delay (1–30s) after display changes before monitor refresh.
- Update UI and resources to reflect new setting and remove old references.
- MainViewModel now uses the configurable delay instead of a hardcoded value.
- Improves user control and reliability of monitor detection after hot-plug events.

src/modules/LightSwitch/LightSwitchService/LightSwitchStateManager.cpp

@@ -4,6 +4,7 @@
 #include <LightSwitchUtils.h>
 #include "ThemeScheduler.h"
 #include <ThemeHelper.h>
+#include <common/interop/shared_constants.h>
 
 void ApplyTheme(bool shouldBeLight);
 
@@ -300,8 +301,8 @@ void LightSwitchStateManager::NotifyPowerDisplay(bool isLight)
         // Using separate events for light/dark eliminates race conditions where PowerDisplay
         // might read the registry before LightSwitch has finished updating it
         const wchar_t* eventName = isLight
-            ? L"Local\\PowerToys_LightSwitch_LightTheme"
-            : L"Local\\PowerToys_LightSwitch_DarkTheme";
+            ? CommonSharedConstants::LIGHT_SWITCH_LIGHT_THEME_EVENT
+            : CommonSharedConstants::LIGHT_SWITCH_DARK_THEME_EVENT;
 
         Logger::info(L"[LightSwitchStateManager] Notifying PowerDisplay about theme change (isLight: {})", isLight);