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/plugin.toml

@@ -0,0 +1,14 @@
+id           = "lux/ideapad-conservation-mode"
+name         = "IdeaPad Conservation Mode"
+version      = "0.3.0"
+min_noctalia = "5.0.0"
+author       = "lux"
+license      = "MIT"
+tags         = ["hardware", "shortcut", "system"]
+icon         = "laptop"
+description  = "Toggles battery conservation mode via the ideapad_acpi driver, on Lenovo IdeaPad and Legion laptops."
+dependencies = ["sudo", "dirname", "env", "bash", "chgrp", "chmod", "getent", "groupadd", "usermod", "cat", "udevadm"]
+
+[[shortcut]]
+id    = "conservation-mode"
+entry = "conservation_mode.luau"