Rulith Inference 0.6.10: downloads no longer stop on a busy progress file

Rulith Inference 0.6.10 fixes model downloads that kept stopping with [Errno 13] Permission denied on state.json (#23).

Downloads

• A download keeps its progress in a small file that it rewrites twice a second, and the Downloads page reads the same file to show the progress. On Windows a file cannot be replaced while another program has it open, and opening it at the moment it is replaced fails as well. When the two met, or a virus scanner looked at the file just then, the download stopped as failed or the page showed a red error. On some machines a large download hit this every minute or two.
• Both sides now wait up to two seconds for the file. A progress update that still cannot be written is skipped, the download goes on, and the next update half a second later writes it.
• A download that cannot read its progress file when it starts now stops instead of starting from empty progress, so it never fetches finished parts again. Resume carries on from where it was.
• Thanks to @biolau, who found the cause and sent a repro.

Everything else is 0.6.9: the runtime and the engine are unchanged.