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/bar.cpp

@@ -263,6 +263,16 @@ waybar::Bar::Bar(struct waybar_output* w_output, const Json::Value& w_config)
 
   window.signal_map_event().connect_notify(sigc::mem_fun(*this, &Bar::onMap));
 
+  window.signal_unmap().connect([this]() {
+    spdlog::debug("Output {} unmapped (DPMS off), suspending modules", output->name);
+    toggleSuspend(true);
+  });
+
+  window.signal_map().connect([this]() {
+    spdlog::debug("Output {} mapped (DPMS on), resuming modules", output->name);
+    toggleSuspend(false);
+  });
+
 #if HAVE_SWAY
   if (auto ipc = config["ipc"]; ipc.isBool() && ipc.asBool()) {
     bar_id = Client::inst()->bar_id;
@@ -545,8 +555,8 @@ void waybar::Bar::getModules(const Factory& factory, const std::string& pos,
           if (group_config["modules"].isNull()) {
             spdlog::warn("Group definition '{}' has not been found, group will be hidden", ref);
           }
-          auto group_module = std::make_unique<waybar::Group>(
-          id_name, class_name, group_config, vertical);
+          auto group_module =
+              std::make_unique<waybar::Group>(id_name, class_name, group_config, vertical);
 
           getModules(factory, ref, group_module.get());
           module = group_module.release();
@@ -696,3 +706,22 @@ void waybar::Bar::configureGlobalOffset(int width, int height) {
 void waybar::Bar::onOutputGeometryChanged() {
   configureGlobalOffset(window.get_width(), window.get_height());
 }
+
+void waybar::Bar::toggleSuspend(bool suspend) {
+  auto process_modules = [suspend](Gtk::Box& module_box) {
+    for (auto* widget : module_box.get_children()) {
+      auto* module = dynamic_cast<waybar::AModule*>(widget);
+      if (module && module->shouldSuspend()) {
+        if (suspend) {
+          module->suspend();
+        } else {
+          module->resume();
+        }
+      }
+    }
+  };
+
+  process_modules(left_);
+  process_modules(center_);
+  process_modules(right_);
+}