Add Cursor Scaler plugin

[wingedtomato]

Add Cursor Scaler to Plugin Store

Cursor Scaler is a Decky plugin that lets users be able to adjust the cursor size in the Steam Deck Gaming Mode.

This is achieved by accessing the /usr/lib/steamos/gamescope-session file, the source of the cursor size. Specifically, the cursor-scale-height in the gamescope flags which determines the actual cursor size. The default is 720, which is about 24px.

By editing the cursor-scale-height this plugin achieves updating the Gaming Mode's cursor size successfully and persists through games played in the Gaming Mode, fully eliminating the need to play games in Desktop Mode for a large cursor size.

Due to the location of the file, this requires a full restart to allow the changes to reflect in Gaming Mode.

Task Checklist

Developer

• I am the original author or an authorized maintainer of this plugin.
• I have abided by the licenses of the libraries I am utilizing, including attaching license notices where appropriate.
• Generative AI was NOT used to write a majority of the code I am submitting.

Plugin

• I have verified that my plugin works properly on the Stable and Beta update channels of SteamOS.
• I have verified my plugin is unique or provides more/alternative functionality to a plugin already on the store.

Backend

• No: I am using a custom backend other than Python.
• No: I am using a tool or software from a 3rd party FOSS project that does not have it's dependencies statically linked.
• No: I am using a custom binary that has all of it's dependencies statically linked.

Community

• I have tested and left feedback on two other pull requests for new or updating plugins.
• I have commented links to my testing report in this PR.

Testing

• Tested by a third party on SteamOS Stable or Beta update channel.

[github-actions]

Issues Found

• Both testing boxes are present in your description. Please remove one of them per the Markdown comment above the testing section.

Next Steps

1. If we found any issues above, please edit your pull request description to resolve them and leave a comment saying you've done so.
2. For the quickest review, please see the Community section of the pull request template for how you can help other developers.
3. Once your description is correct, a maintainer will review your pull request as soon as possible.

Thank you for your contribution! If you need any help, please reach out on our Discord server. ❤️