Fix Toast timing and alert once per shown Toast

- ToastQueue compared times unsigned: a Toast stamped a few ms after the
  main loop read the clock looked expired, so Toasts were skipped or
  shown late and bursts chained wrongly
- Notifier now beeps and flashes when each Toast appears instead of when
  the Notification arrives, so a burst alerts once per Toast

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

src/ui/notifier.cpp

@@ -9,14 +9,12 @@ constexpr int kLedPin = 21;  // WS2812, powered with the backlight rail (G38)
 }
 
 Notifier::Notifier(EventBus& bus, const Settings& settings) : settings_(settings) {
-    bus.subscribe(EventType::Notification, [this](const Event& e) { present(e); });
+    bus.subscribe(EventType::Notification, [this](const Event& e) {
+        toasts_.push(e.text, static_cast<NotificationLevel>(e.a), millis());
+    });
 }
 
-void Notifier::present(const Event& e) {
-    auto level = static_cast<NotificationLevel>(e.a);
-    uint32_t now = millis();
-    toasts_.push(e.text, level, now);
-
+void Notifier::alert(NotificationLevel level, uint32_t nowMs) {
     if (!settings_.getBool(Setting::Sound)) return;
     M5Cardputer.Speaker.tone(level == NotificationLevel::Warning ? 880 : 1760, 60);
     switch (level) {
@@ -25,10 +23,15 @@ void Notifier::present(const Event& e) {
         default: rgbLedWrite(kLedPin, 0, 16, 40); break;
     }
     ledOn_ = true;
-    ledOffAtMs_ = now + 150;
+    ledOffAtMs_ = nowMs + 150;
 }
 
 void Notifier::update(uint32_t nowMs) {
+    const Toast* shown = toasts_.current(nowMs);
+    if (shown && shown->id != alertedId_) {
+        alertedId_ = shown->id;
+        alert(shown->level, nowMs);
+    }
     if (ledOn_ && static_cast<int32_t>(nowMs - ledOffAtMs_) >= 0) {
         rgbLedWrite(kLedPin, 0, 0, 0);
         ledOn_ = false;