Edit pyproject.toml file's tool.uv.sources option if it is a uv-managed project

[erral]

For uv-managed projects (those with [tool.uv] managed=true in pyproject.toml) write in the [tool.uv.sources] option of the pyproject.toml the paths to the downloaded packages.

See erral/mxdev-uv-pyproject-updater#1 and plone/cookieplone-templates#352 for reference

[stevepiercy]

Fixed heading

[jensens]

Feature concept is sound but needs rework in a few areas before merge. See inline comments.

[erral]

Thank you both for the review, I have updated the code to match your review notes.

[erral]

Gemini suggested doing the if typing.TYPE_CHECKING thing for lint phase to pass: https://docs.python.org/3/library/typing.html#typing.TYPE_CHECKING

[jensens]

Most prior issues addressed well. One critical ordering bug remains, plus a few smaller items.

[jensens]

Looks good. All critical issues addressed. Minor simplification opportunities remain (the TYPE_CHECKING dance at runtime, the triple-layer managed check, bare except on tomllib) — we can clean those up in a follow-up.