Wsgo

- Fix GLIBC_TUNABLES syntax
- Add blocking facility
- Add arm64 build

- Add Python 3.13 build

- Only apply user-agent based bot-limiting to non-local, non-private IPs, so that recursive requests that resemble bots (such as from Weasyprint) don't deadlock.

- Add workaround for deadlocks caused by interrupting stuck workers whilst they hold the logging lock.
- Raise `wsgo.RequestTimeoutException` instead of `InterruptedError` on request timeouts.
- Report active request (and per-IP) statistics in response to USR2 signals.

- Fix a bug where the rate limit key was "::" for IPv4 addresses, meaning all requests shared the same rate limit pool, causing legitimate requests to be throttled incorrectly.
- Removed the average-CPU-time-by-URL prioritisation method, because it was causing problems, for example where a few accesses to the homepage under heavy load result in a high recorded average CPU time for the homepage, which then caused future homepage requests to be prioritised lower than bot traffic, resulting in lagging and timeouts.

- Call close() on WSGI response objects after the response is finished (if such a method exists)
- Use PyEval_SaveThread instead of PyGILState_Release at the end of worker tasks to avoid thread state being purged, which was causing threading.local to forget its contents between requests.