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

@@ -206,35 +206,38 @@ void DisplayIdleService::tick() {
     auto display = getDisplay();
     bool supportsBacklight = display != nullptr && display->supportsBacklightDuty();
 
-    if (supportsBacklight) {
-        if (!cachedDisplaySettings.backlightTimeoutEnabled || cachedDisplaySettings.backlightTimeoutMs == 0) {
-            if (displayDimmed && !isMcpActive) {
+    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 {
-            bool charging_blocks = cachedDisplaySettings.disableScreensaverWhenCharging && isDeviceCharging();
+            displayDimmed = false;
+        }
+    } else {
+        bool charging_blocks = cachedDisplaySettings.disableScreensaverWhenCharging && isDeviceCharging();
 
-            if (!displayDimmed && inactive_ms >= cachedDisplaySettings.backlightTimeoutMs) {
-                if (charging_blocks) {
-                    // Skip screensaver while charging
-                } else {
-                    if (!lvgl::lock(100)) {
-                        return; // Retry on next tick
-                    }
-                    activateScreensaver();
-                    lvgl::unlock();
-                    if (cachedDisplaySettings.screensaverType == settings::display::ScreensaverType::None) {
+        if (!displayDimmed && inactive_ms >= cachedDisplaySettings.backlightTimeoutMs) {
+            if (charging_blocks) {
+                // Skip screensaver while charging
+            } else {
+                if (!lvgl::lock(100)) {
+                    return; // Retry on next tick
+                }
+                activateScreensaver();
+                lvgl::unlock();
+                if (cachedDisplaySettings.screensaverType == settings::display::ScreensaverType::None) {
+                    if (supportsBacklight && display != nullptr) {
                         display->setBacklightDuty(0);
                     }
-                    displayDimmed = true;
-                }
-            } else if (displayDimmed && !isMcpActive) {
-                if (inactive_ms < kWakeActivityThresholdMs) {
-                    stopScreensaver();
-                } else if (charging_blocks) {
-                    stopScreensaver();
                 }
+                displayDimmed = true;
+            }
+        } else if (displayDimmed && !isMcpActive) {
+            if (inactive_ms < kWakeActivityThresholdMs) {
+                stopScreensaver();
+            } else if (charging_blocks) {
+                stopScreensaver();
             }
         }
     }