feat(config): wire up wallpapers_dir, osd, window_switcher, global_menu settings

- wallpapers_dir: read from config, fallback ~/Pictures/Wallpapers
- osd: skip show_audio_osd/show_brightness_osd when disabled
- window_switcher: skip show_switcher when disabled
- global_menu_cache_enabled: bypass GTK class cache when false
- global_menu_method: control discovery strategies (auto/hyprland/dbus)

All keys added to constants.py defaults, settings UI, and config.toml

src/window/osd/main.py

@@ -38,9 +38,17 @@ class OSD(Box):
         self.revealer.set_reveal_child(True)
 
     def show_audio_osd(self):
+        from services.config import get_config
+
+        if not get_config("osd", True):
+            return
         self.show_container(self.containers.get("audio"))
 
     def show_brightness_osd(self):
+        from services.config import get_config
+
+        if not get_config("osd", True):
+            return
         self.show_container(self.containers.get("brightness"))