Restore python 3.6 and update CI to import module after installing

[tynanford]

#177

This updates processors.py and recast.py to work with python3.6 and above - updated type hints and remove removeprefix which is >=3.9

Had claude help with updating the CI. It now actually imports the package as @anderslindho mentioned and manually installs the pip packages for 3.6 since setuptools on 3.6 doesn't work with the pyproject.toml setup. Claude also found an issue with the pyproject.toml file: The <3.8 and <3.7 lines for requests and twisted overlap for python 3.6.

[anderslindho]

Unfortunately this doesn’t work as-is - note Successfully installed UNKNOWN-0.0.0 in the 3.6 build log.

We’ll have to reintroduce setup.cfg, move the [project] / package metadata out of pyproject.toml, pin setuptools to something that still runs on 3.6, and fix the smoke test: right now PYTHONPATH=. imports from the checkout even when install failed, so it can’t catch this. After a real pip install ., run the import from /tmp (or any dir outside server/) so it has to use the installed package. We should probably also set ruff to py37 (it doesn’t support 36).

[sonarqubecloud]

Quality Gate failed

Failed conditions
C Security Rating on New Code (required ≥ A)

See analysis details on SonarQube Cloud

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[tynanford]

Ah, good catch. Instead of reverting back to setup.cfg I propose we just have the CI test the import without installing it as a package. Confirmed in a test commit here that the CI will fail for py3.6 - py3.8 with set keyword: https://github.com/ChannelFinder/recsync/actions/runs/31213348556

Sonarqube is complaining i think because we don't have pinned exact versions in the pyproject.toml file. To me it seems like something that could be dismissed?