add charging watchdog

user/dot_config/systemd/user/battery-charge-watchdog.service

@@ -0,0 +1,32 @@
+[Unit]
+Description=Battery charge-controller fault watchdog
+Documentation=man:notify-send(1)
+# Needs the session bus for notifications.
+After=graphical-session.target
+PartOf=graphical-session.target
+# Makes the unit inert on machines without a battery, so it can be
+# enabled unconditionally on the desktop as well as the laptop.
+ConditionPathExists=/sys/class/power_supply/BAT0/charge_now
+
+[Service]
+Type=simple
+ExecStart=%h/.config/scripts/battery-charge-watchdog.sh
+Restart=always
+RestartSec=10
+
+# Set HIBERNATE_AT=5 to add an emergency hibernate floor (0 = notify only).
+Environment=POLL_INTERVAL=20
+Environment=REPEAT_INTERVAL=60
+Environment=DROP_PERMILLE=15
+Environment=HIBERNATE_AT=0
+
+# Read-only monitoring; no need for any write access to the system.
+ProtectSystem=strict
+ProtectHome=read-only
+PrivateTmp=yes
+NoNewPrivileges=yes
+RestrictNamespaces=yes
+MemoryMax=64M
+
+[Install]
+WantedBy=graphical-session.target