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/README.md

@@ -0,0 +1,38 @@
+# IdeaPad Conservation Mode
+![IdeaPad Conservation Mode thumbnail](thumbnail.webp)
+
+**IdeaPad Conservation Mode** is a Control Center shortcut plugin for [Noctalia](https://docs.noctalia.dev) (v5) that toggles **Conservation Mode** — capping charging around ~60% to preserve battery health — via the `ideapad_acpi` kernel driver's `conservation_mode` sysfs attribute. That driver covers Lenovo IdeaPad and Legion laptops alike, not just Legion.
+
+Writing that attribute needs root by default. The first time you click the tile and the write fails, the plugin opens a terminal and runs a bundled one-time setup script with `sudo`. It creates a `lenovoctl` group, adds you to it, and installs a udev rule so future writes are unprivileged. Log out and back in once afterward; every click after that just works, with no further prompts.
+
+## Plugin
+
+| Field | Value |
+| --- | --- |
+| ID | `lux/ideapad-conservation-mode` |
+| Entries | Shortcut: `conservation-mode` |
+
+## Requirements
+
+The bundled setup script (`scripts/setup-permissions.sh`) shells out to `sudo`, `dirname`, `env`, `bash`, `chgrp`, `chmod`, `getent`, `groupadd`, `usermod`, `cat`, and `udevadm`. All of these ship by default on essentially every mainstream Linux distribution (coreutils, util-linux, shadow-utils, systemd/udev).
+
+## Usage
+
+Add the `conservation-mode` shortcut under Settings → Control Center shortcuts. Click it to toggle Conservation Mode; the label shows the current state (On / Off / N/A if the sysfs attribute can't be found). The first click may open a terminal for the one-time `sudo` setup described above.
+
+## NixOS
+
+`/etc/udev/rules.d` is generated from system config on NixOS, so the setup script exits instead of writing to it. Add the equivalent declaratively instead:
+
+```nix
+{
+  users.groups.lenovoctl = {};
+  users.users.<your-username>.extraGroups = [ "lenovoctl" ];
+
+  services.udev.extraRules = ''
+    ACTION=="add|change", SUBSYSTEM=="platform", DRIVER=="ideapad_acpi", RUN+="${pkgs.coreutils}/bin/chgrp lenovoctl /sys%p/conservation_mode", RUN+="${pkgs.coreutils}/bin/chmod 664 /sys%p/conservation_mode"
+  '';
+}
+```
+
+Rebuild, log out and back in, then click the tile.