feat(arch): add pacman hook to notify waybar of update

roles/arch-post-setup/files/pacman-hooks/inform-waybar.hook

@@ -0,0 +1,10 @@
+# vim: filetype=systemd
+[Trigger]
+Operation = Upgrade
+Type = Package
+Target = *
+
+[Action]
+Description = Inform waybar about pacman upgrade finishing
+When = PostTransaction
+Exec = /usr/bin/pkill -SIGRTMIN+8 waybar

roles/arch-post-setup/tasks/main.yml

@@ -194,3 +194,4 @@
     - disable-gpu.yml
     - dns.yml
     - powertop.yml
+    - pacman-hooks.yml

roles/arch-post-setup/tasks/pacman-hooks.yml

@@ -0,0 +1,18 @@
+---
+- name: Ensure /etc/pacman.d/hooks/ directory exists
+  become: true
+  ansible.builtin.file:
+    path: /etc/pacman.d/hooks
+    state: directory
+    mode: '0755'
+    owner: root
+    group: root
+
+- name: Install Pacman Hooks
+  become: true
+  ansible.builtin.copy:
+    src: pacman-hooks/
+    dest: /etc/pacman.d/hooks/
+    mode: '0644'
+    owner: root
+    group: root