Add systemd timers to auto-mute/unmute when idle-inhibit is active

Mutes audio at 21:00 and unmutes at 07:00, but only when the
idle-inhibit toggle is active (PID file exists). This is useful
for leaving the computer running overnight for SSH access while
keeping it quiet for sleeping.

README.md

@@ -73,6 +73,17 @@ ln -s ~/Projects/hypr-dotfiles/kitty kitty
 ln -s ~/Projects/hypr-dotfiles/helix helix
 ```
 
+To enable the auto-mute/unmute timers (mutes at 21:00, unmutes at
+07:00, only when idle-inhibit is active), link the systemd user units:
+
+```
+systemctl --user link ~/Projects/hypr-dotfiles/systemd/user/auto-mute.service
+systemctl --user link ~/Projects/hypr-dotfiles/systemd/user/auto-mute.timer
+systemctl --user link ~/Projects/hypr-dotfiles/systemd/user/auto-unmute.service
+systemctl --user link ~/Projects/hypr-dotfiles/systemd/user/auto-unmute.timer
+systemctl --user enable --now auto-mute.timer auto-unmute.timer
+```
+
 You also need to install all the dependencies:
 
 - hyprland

systemd/user/auto-mute.service

@@ -0,0 +1,7 @@
+[Unit]
+Description=Mute audio when idle-inhibit is active
+
+[Service]
+Type=oneshot
+ExecCondition=/bin/bash -c 'test -f ${XDG_RUNTIME_DIR}/idle-inhibit.pid && kill -0 $(cat ${XDG_RUNTIME_DIR}/idle-inhibit.pid)'
+ExecStart=/usr/bin/wpctl set-mute @DEFAULT_AUDIO_SINK@ 1

systemd/user/auto-mute.timer

@@ -0,0 +1,9 @@
+[Unit]
+Description=Mute audio at 21:00
+
+[Timer]
+OnCalendar=*-*-* 21:00:00
+Persistent=false
+
+[Install]
+WantedBy=timers.target

systemd/user/auto-unmute.service

@@ -0,0 +1,7 @@
+[Unit]
+Description=Unmute audio when idle-inhibit is active
+
+[Service]
+Type=oneshot
+ExecCondition=/bin/bash -c 'test -f ${XDG_RUNTIME_DIR}/idle-inhibit.pid && kill -0 $(cat ${XDG_RUNTIME_DIR}/idle-inhibit.pid)'
+ExecStart=/usr/bin/wpctl set-mute @DEFAULT_AUDIO_SINK@ 0

systemd/user/auto-unmute.timer

@@ -0,0 +1,9 @@
+[Unit]
+Description=Unmute audio at 07:00
+
+[Timer]
+OnCalendar=*-*-* 07:00:00
+Persistent=false
+
+[Install]
+WantedBy=timers.target