PowerPulse: add wireless battery monitor desklet

[vicman]

Summary

• Add the PowerPulse desklet (powerpulse@vicman.app) to Cinnamon Spices.
• Compact wireless battery monitor using UPower and optional HeadsetControl.
• Version 1.3.0: hover details popover, voltage/age, native installer in the upstream repo.

Upstream project: https://github.com/vicman/PowerPulse
Release: https://github.com/vicman/PowerPulse/releases/tag/v1.3.0

Test plan

• Install from this spice folder into ~/.local/share/cinnamon/desklets/
• Reload Cinnamon (Alt+F2 → r)
• Add PowerPulse from Desklets settings
• Confirm UPower devices appear
• Hover a device and confirm the details panel

[github-actions]

Best-practices scanner

This is a regex-based check for API usage that can pose security, performance or
maintainability issues, or that may already be provided by Cinnamon. Most findings
are advisory and do not automatically disqualify a pull request.

This check is not perfect and will not replace a normal review.

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Found 2 potential issue(s):

⚠️ WARNING

⚠️ sync_file_test

powerpulse@vicman.app/files/powerpulse@vicman.app/desklet.js:49

if (GLib.file_test(mo, GLib.FileTest.IS_REGULAR)) {

file_test() is a synchronous stat call that can block on slow/network filesystems.
Prefer attempting the operation and handling a Gio.IOErrorEnum.NOT_FOUND error instead.

ℹ️ INFO

ℹ️ shell_string_spawn

powerpulse@vicman.app/files/powerpulse@vicman.app/desklet.js:641

Util.spawnCommandLine(command);

Prefer argument vector spawn functions over shell command strings.
This is especially important when arguments include untrusted input (user data,
filenames, settings values, etc.) as shell strings are vulnerable to injection.
Static command strings are generally fine, but argv is always safer.
Use Util.spawn(["cmd", "arg1", "arg2"]) or Util.trySpawn() instead.

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Automated pattern check.