fix failing CI, update python versions

[jakkdl]

drop 3.8 testing+support
remove some 3.7 remnants
add 3.13 and 3.14 testing+support
silence pytest-asyncio deprecationwarning
fix typing errors
fix pep8 errors
fix poetry warning

incorporates #271 and #272

this code base would also benefit from running flake8-upgrade (or similar) and replace all imports from typing that can be replaced with standard objects (e.g. List -> list) but I thought this PR was big enough already.

[jakkdl]

ugh, the runners don't have 24.04 + x64 + 3.14. They do have builds for 24.04 + 3.14 with other architectures, and 22.04 + x64 + 3.14.

Up to you if you want to keep it in ci.yml until it's available (presumably they'll have more builds once it exits the beta), remove it, do fancy matrix stuff for the ubuntu version, or whatever. @pgjones