Light the screen (dimmed) while a Notification's Toast shows

An Off screen turns on dimmed for the Toast's duration so the user can
see what beeped. It isn't user activity: the timeouts aren't restarted,
and a key pressed meanwhile reaches the App.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01EhqxQ49eCju4CzKYNjZzwT

lib/services/src/power_policy.cpp

@@ -12,6 +12,12 @@ bool PowerPolicy::activity(uint32_t nowMs) {
 ScreenState PowerPolicy::update(uint32_t nowMs) {
     uint32_t idle = nowMs - lastActivityMs_;
     state_ = idle >= offMs_ ? ScreenState::Off : idle >= dimMs_ ? ScreenState::Dimmed : ScreenState::On;
+    if (notifying_) {
+        if (static_cast<int32_t>(nowMs - notifyUntilMs_) >= 0)
+            notifying_ = false;
+        else if (state_ == ScreenState::Off)
+            state_ = ScreenState::Dimmed;
+    }
     return state_;
 }