feat(doorbell): add inactivity timeout to turn off screen

libraries/KlubhausCore/src/Config.h

@@ -16,6 +16,7 @@
 #define HOLD_TO_SILENCE_MS 3000
 #define ALERT_TIMEOUT_MS 120000
 #define SILENCE_DISPLAY_MS 10000
+#define INACTIVITY_TIMEOUT_MS 30000
 #define WIFI_CONNECT_TIMEOUT_MS 15000
 #define HTTP_TIMEOUT_MS 10000
 #define HINT_ANIMATION_MS 2000

libraries/KlubhausCore/src/DoorbellLogic.cpp

@@ -79,6 +79,7 @@ void DoorbellLogic::finishBoot() {
     _display->setBacklight(false);
     _state.backlightOn = false;
     _bootGraceEnd = millis() + BOOT_GRACE_MS;
+    _lastActivityMs = millis();
     Serial.printf("[BOOT] Grace period: %d ms\n", BOOT_GRACE_MS);
     Serial.printf("[BOOT] Ready — monitoring %s\n", NTFY_SERVER);
 }
@@ -130,6 +131,13 @@ void DoorbellLogic::update() {
         }
         break;
     default:
+        // Inactivity timeout: turn off screen after no activity
+        if(_state.screen != ScreenID::OFF && now - _lastActivityMs > INACTIVITY_TIMEOUT_MS) {
+            Serial.println("[STATE] Inactivity timeout → OFF");
+            _state.screen = ScreenID::OFF;
+            _display->setBacklight(false);
+            _state.backlightOn = false;
+        }
         break;
     }
 }
@@ -300,6 +308,9 @@ int DoorbellLogic::handleTouch(const TouchEvent& evt) {
     if(!evt.pressed)
         return -1;
 
+    // Reset inactivity timer on any touch
+    _lastActivityMs = millis();
+
     if(_state.screen == ScreenID::OFF) {
         Serial.println("[TOUCH] OFF → DASHBOARD");
         setScreen(ScreenID::DASHBOARD);

libraries/KlubhausCore/src/DoorbellLogic.h

@@ -57,6 +57,7 @@ private:
 
     uint32_t _lastPollMs = 0;
     uint32_t _lastHeartbeatMs = 0;
+    uint32_t _lastActivityMs = 0;
     uint32_t _bootGraceEnd = 0;
 
     String _alertUrl;