feat(lint): enable ruff TCH (flake8-type-checking) rules

[shiftinv]

Summary

Enables ruff's TCH rules (flake8-type-checking) -- see #1124.

TCH001-TCH003 are left disabled for now, since those are not trivial to take care of in some places. The important one in our case is TCH004 anyway.

The code changes in this PR are to satisfy the new rules, they weren't actual issues (unlike #1124). As mentioned, TCH004 isn't perfect and has a couple edge cases, particularly when it comes to submodule imports.

Checklist

• If code changes were made, then they have been tested
  • I have updated the documentation to reflect the changes
  • I have formatted the code properly by running pdm lint
  • I have type-checked the code by running pdm pyright
• This PR fixes an issue
• This PR adds something new (e.g. new method or parameters)
• This PR is a breaking change (e.g. methods or parameters removed/renamed)
• This PR is not a code change (e.g. documentation, README, ...)