[pomodoro] Add notification sound

[thepunkoff]

Plugin

• Id: thepunkoff/pomodoro
• New plugin
• Update to an existing plugin (version bumped in plugin.toml)

What it does

Implements #255: Adds an optional notification sound that will play when work/break is over.

External dependencies

pw-play

Testing

• Tested on Niri
• Tested on Hyprland
• Tested on Sway
• Tested on another compositor:
• Noctalia version tested against: noctalia v5.0.0 (v5.0.0-beta.6-26-g5ef0f897bef4)
• Plugin API level: 3

Screenshots / Videos

n/a

Checklist

• The directory name matches the part of id after the / in plugin.toml exactly.
• It ships plugin.toml, README.md, thumbnail.webp, and translations/en.json.
• README.md follows the
  README template, documents
  every entry id and dependency, and includes exact panel IPC commands and launcher prefixes where applicable.
• I created thumbnail.webp with the thumbnail generator.
• version follows semver and is bumped in this PR; plugin_api is the oldest API level this plugin requires.
• Every non-English translation in this PR uses a locale supported by Noctalia core, and I can read, write, and
  understand that language well enough to review and maintain it (no unreviewed machine/LLM translations).
• I did not edit catalog.toml; CI generates it.
• This PR touches exactly one plugin directory.

Code review attestation

Plugins run as trusted, unsandboxed Luau in the user's session. Confirm:

• The code is readable and not obfuscated, minified, or generated.
• It does not download and execute remote code.
• Every network call, filesystem write, and spawned process is something the description above accounts for.
• I have the right to publish this code under the license declared in plugin.toml.

[thepunkoff]

I should probably use the new sounds API, please don't merge yet