feat(modules): pause background threads when display is asleep

Currently, modules polling hardware nodes continuously wake up kernel drivers even when the monitor is asleep (e.g., DPMS off), flooding dmesg.

- Adds 'disable-on-sleep' config flag
- Hooks GTK window map/unmap signals to track DPMS state
- Propagates suspend/resume calls to AModule worker threads

src/modules/temperature.cpp

@@ -155,3 +155,7 @@ bool waybar::modules::Temperature::isCritical(uint16_t temperature_c) {
   return config_["critical-threshold"].isInt() &&
          temperature_c >= config_["critical-threshold"].asInt();
 }
+
+void waybar::modules::Temperature::suspend() { thread_.pause(); }
+
+void waybar::modules::Temperature::resume() { thread_.resume(); }