Proposal: Mirror repository on SourceHut and/or Codeberg for accessibility and vendor independence

I'd like to propose mirroring the iSH repository on SourceHut and/or Codeberg in addition to GitHub. This would provide benefits for accessibility, reduce vendor lock-in, and better serve users who prefer to avoid proprietary JavaScript.

Currently, iSH is only hosted on GitHub. While GitHub is convenient, this creates several friction points:
- JavaScript concerns: GitHub's web interface relies heavily on proprietary JavaScript, which can be problematic for users who prefer lightweight browsing, prefer to avoid proprietary software, or use JS-blocking tools.
- Vendor lock-in: Hosting only on a single proprietary platform makes the project dependent on GitHub's continued availability and policies.
- User choice: Some users prefer forges that align with open-source principles (like SourceHut or Codeberg), and mirrors would make the project more accessible to them without requiring GitHub accounts.

I propose maintaining mirrors on either:
- SourceHut (preferred, due to minimal JS and accessibility-first design)
- Codeberg (Forgejo-based, community-driven alternative)

These could be read-only mirrors synced from the primary GitHub repo, or if preferred, full mirrors where contributions are accepted via pull requests on either platform. A simple automated sync (like a cron job or webhook) could keep them current with minimal overhead.
I understand you are unpaid open source maintainers working out of your free time so I respect your opinion if you find it too inconvenient. I'd also be happy to help set up and maintain the mirrors if that would ease the burden.

Start by reviewing the iSH GitHub repository and comparing the proposed SourceHut and Codeberg hosting options. Evaluate whether the project wants read-only mirrors or accepts contributions on both platforms, then determine the synchronization approach, such as a cron job or webhook. Done means a maintainer-approved hosting and maintenance plan is established.

Written by the indexing model from the issue text.