Add IdeaPad Conservation Mode plugin (#20)

* feat: add lux/ideapad-conservation-mode plugin

* fix: address review blockers on ideapad-conservation-mode

- shell-quote pluginDir/USER before splicing into the sudo/runInTerminal
  command (shell injection)
- declare every external command setup-permissions.sh invokes as a
  manifest dependency, and document them in README Requirements
- drop the hardcoded KERNEL=="VPC2004:00" match from the udev rule so it
  matches any ideapad_acpi instance, consistent with the dynamic
  discovery the Luau side already does
- add the promised NixOS declarative setup section to README
- move all user-visible strings out of conservation_mode.luau into
  translations/en.json, accessed via noctalia.tr()
- add the required README Plugin/Usage sections

* Update dependencies in plugin.toml

* Update setup script requirements in README.md

---------

Co-authored-by: Lemmy <studio@quadbyte.net>

ideapad-conservation-mode/scripts/setup-permissions.sh

@@ -0,0 +1,51 @@
+#!/usr/bin/env bash
+# One-time setup: lets the "lenovoctl" group toggle Lenovo IdeaPad/Legion ACPI
+# features (currently battery conservation_mode) without root.
+#
+# Run via sudo (the plugin invokes this itself, in a terminal, the first time
+# a write fails). Idempotent -- safe to re-run.
+#
+# NOTE: udev's GROUP=/MODE= rule keys only apply to the /dev device node they
+# create, NOT to arbitrary sysfs ATTR files (see udev(7)) -- a rule matching
+# ATTR{conservation_mode} with GROUP=/MODE= is a silent no-op here. We use
+# RUN+= to chmod/chgrp the resolved sysfs path directly instead.
+set -euo pipefail
+
+if [ "$EUID" -ne 0 ]; then
+  echo "Run this with sudo." >&2
+  exit 1
+fi
+
+TARGET_USER="${SUDO_USER:-${1:-}}"
+if [ -z "$TARGET_USER" ]; then
+  echo "No target user specified (expected \$SUDO_USER or \$1)." >&2
+  exit 1
+fi
+
+GROUP_NAME=lenovoctl
+RULE_FILE=/etc/udev/rules.d/99-ideapad-conservation-mode.rules
+
+if [ ! -w "$(dirname "$RULE_FILE")" ]; then
+  echo "Cannot write to $(dirname "$RULE_FILE") -- this looks like an immutable" >&2
+  echo "/etc (e.g. NixOS, where udev rules are generated from system config)." >&2
+  echo "See this plugin's README.md for the declarative NixOS setup instead." >&2
+  exit 1
+fi
+
+CHGRP_BIN="$(command -v chgrp)"
+CHMOD_BIN="$(command -v chmod)"
+
+echo "Creating group '$GROUP_NAME' (if missing) and adding $TARGET_USER..."
+getent group "$GROUP_NAME" >/dev/null || groupadd "$GROUP_NAME"
+usermod -aG "$GROUP_NAME" "$TARGET_USER"
+
+echo "Writing $RULE_FILE..."
+cat >"$RULE_FILE" <<EOF
+ACTION=="add|change", SUBSYSTEM=="platform", DRIVER=="ideapad_acpi", RUN+="$CHGRP_BIN $GROUP_NAME /sys%p/conservation_mode", RUN+="$CHMOD_BIN 664 /sys%p/conservation_mode"
+EOF
+
+echo "Reloading udev rules..."
+udevadm control --reload-rules
+udevadm trigger --subsystem-match=platform
+
+echo "Done."