Enhance Sway/Noctalia integration and align desktop docs

- Add canonical usb-drive-manager plugin to Noctalia (symlink from official)
- Remove nm-applet and blueman packages from nymph Sway session
- Run udiskie without tray (backend for automount/LUKS, UI via usb-drive-manager)
- Add screenOverrides support to Noctalia bar via inventory variables
- Add host_packages_absent task to packages_void role
- Update desktop docs with full plugin list and config layering
- Add focused validation check for Sway/Noctalia bootstrap

ansible/roles/packages_void/tasks/main.yml

@@ -71,4 +71,11 @@
         | unique
       }}
     state: present
-    update_cache: false
+    update_cache: false
+
+- name: Remove host-absent packages on Void Linux
+  tags: [packages]
+  community.general.xbps:
+    name: "{{ host_packages_absent | default([]) }}"
+    state: absent
+  when: (host_packages_absent | default([])) | length > 0