sl0ppty: ruff format the Python

The bumpy one, again. Every `.py` outside `vendor/` plus the three `contrib/`
scripts that are Python with no extension: 60 files, 6,714 lines rewritten, no
behaviour changed. Nothing here is worth reading -- the next commit adds it to
`.git-blame-ignore-revs` so `git blame` walks past it.

It is a bigger reformat than the C was, 60% of the lines against 17%, and for a
reason worth writing down rather than tuning away: ruff and black break a call that
does not fit onto one argument per line, where this code aligned the continuation
under the opening paren. The test suite is thousands of `check("some prose", cond,
detail)` calls, so nearly every one of them changed shape and the suite grew 3,308
lines. Line length was the one lever that moved it -- 120 columns would have been a
40% reformat and no growth at all -- and it was left at 88, because picking an
unusual width to dodge a one-time diff is paying forever to avoid paying once.

Import sorting came with it. Two files had `import os, pty, uuid, select, struct,
sys, termios, time, fcntl, signal` on one line and now have ten.

Verified after, not before, because a formatter that alters behaviour would be
worse than none:

- `make retest`, 1801 checks green -- and this reformats the suite that does the
  checking, including `harness.py`, which every one of those files imports.
- `make test-live`, the tty tests the fast suite skips. They matter here more than
  usual: `live_input.py` and `live_m0.py` are two of the files whose comma-imports
  were split, and nothing in the fast suite would have noticed if that broke them.
- All 60 files still compile, `make fmt` twice in a row changes nothing the second
  time, and `ruff check --select I` has nothing left to say.

0 files changed, 0 insertions, 0 deletions