chore: initialize gentoo-setup documentation repository

Add comprehensive documentation for Lenovo ThinkPad Gentoo Linux setup
including:
- Complete system configuration guides (power, Bluetooth, WiFi, audio)
- Hardware setup documentation (touchpad, touchscreen, DisplayLink)
- Management scripts with ZSH completions
- Kernel configuration (6.12.41-gentoo-x86_64)
- Lid automation and monitor management
- Battery conservation system
- User guides and troubleshooting

Repository includes .gitignore to exclude logs, temporary files, and
secrets.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

scripts/battery-setup/battery-thresholds

@@ -0,0 +1,43 @@
+#!/sbin/openrc-run
+# OpenRC init script for battery charge thresholds
+# Restore battery charge thresholds on boot
+
+description="Set battery charge thresholds for battery health"
+
+BATTERY="${BATTERY:-BAT0}"
+START_THRESHOLD="${START_THRESHOLD:-20}"
+END_THRESHOLD="${END_THRESHOLD:-80}"
+
+depend() {
+    need localmount
+}
+
+start() {
+    ebegin "Setting battery charge thresholds"
+
+    if [ ! -d "/sys/class/power_supply/$BATTERY" ]; then
+        eerror "Battery $BATTERY not found"
+        eend 1
+        return 1
+    fi
+
+    if [ ! -f "/sys/class/power_supply/$BATTERY/charge_control_start_threshold" ]; then
+        eerror "Battery charge thresholds not supported"
+        eend 1
+        return 1
+    fi
+
+    # Set start threshold
+    echo "$START_THRESHOLD" > "/sys/class/power_supply/$BATTERY/charge_control_start_threshold"
+
+    # Set end threshold
+    echo "$END_THRESHOLD" > "/sys/class/power_supply/$BATTERY/charge_control_end_threshold"
+
+    einfo "Battery thresholds set: ${START_THRESHOLD}% - ${END_THRESHOLD}%"
+    eend $?
+}
+
+stop() {
+    # Nothing to do on stop
+    return 0
+}