fix(rlcd): screensaver wake/activate must run for monochrome, not just backlight displays

RLCD ST7305 has !supportsBacklightDuty(). Previous fix that fixed MCP flash-then-back left entire idle state machine gated by supportsBacklight, causing once dimmed it could never wake on button press -> appears locked weird state reported.

Fix: run timeout logic for all displays, guard only setBacklightDuty calls.
- timeout disabled (Never) branch always restores displayDimmed
- timeout activation creates screensaver for all
- wake on inactive<100ms + charging block works for RLCD
- setBacklightDuty only when supportsBacklight && display!=nullptr

Also preserves deadlock-free ordering (MCP state outside LVGL lock) from 3629ffef.

RLCD: 0x2b78b0 32%% free flashed /dev/cu.usbmodem101

Co-Authored-By: internal-model

Tactility/Source/service/displayidle/DisplayIdle.cpp

@@ -206,10 +206,12 @@ void DisplayIdleService::tick() {
     auto display = getDisplay();
     bool supportsBacklight = display != nullptr && display->supportsBacklightDuty();
 
-    if (supportsBacklight) {
     if (!cachedDisplaySettings.backlightTimeoutEnabled || cachedDisplaySettings.backlightTimeoutMs == 0) {
+        // Timeout disabled (Never): ensure we restore if we were dimmed, regardless of display type
         if (displayDimmed && !isMcpActive) {
+            if (supportsBacklight && display != nullptr) {
                 display->setBacklightDuty(cachedDisplaySettings.backlightDuty);
+            }
             displayDimmed = false;
         }
     } else {
@@ -225,8 +227,10 @@ void DisplayIdleService::tick() {
                 activateScreensaver();
                 lvgl::unlock();
                 if (cachedDisplaySettings.screensaverType == settings::display::ScreensaverType::None) {
+                    if (supportsBacklight && display != nullptr) {
                         display->setBacklightDuty(0);
                     }
+                }
                 displayDimmed = true;
             }
         } else if (displayDimmed && !isMcpActive) {
@@ -238,7 +242,6 @@ void DisplayIdleService::tick() {
         }
     }
 }
-}
 
 bool DisplayIdleService::onStart(ServiceContext& service) {
     // Seed random number generator for varied screensaver patterns