PR #553 follow-ups: presubmit.py's preflight comment describes a removed check nf-qmbi ← Beads

Twinned from https://github.com/cfsh/ninefold/issues/556 by tools/beads/import_github.py's reconcile pass.

Suggestions from ninefold-reviewer's review of #553. Not gating — #553 is CONVERGED with this outstanding, and it is pre-existing text that PR neither introduced nor contradicted. Same family as the three #553 fixed, one file over.

presubmit.py:53-56 justifies the --doctor preflight bypass with a check that no longer exists

```python # nflib runs check_interpreter() at import, which raises PreflightError when # python on PATH is the Microsoft Store stub. That is the headline case # CLAUDE.md documents this flag for ("run this first on a new box") — and it # made --doctor die during import, before main() ever ran, ... ```

Present tense, and false since #436. tools/nflib/__init__.py:107-118 (check_interpreter) does one thing now — sys.executable is empty or does not exist — and never looks at PATH. Its own docstring says so explicitly:

> The earlier version also asserted that the python on PATH was not the Microsoft Store stub, detecting it by path … That heuristic is now provably wrong

So the comment describes the *removed* version of the guard as the live reason for os.environ.setdefault("NFLIB_SKIP_PREFLIGHT", "1") at presubmit.py:65-66. The bypass is still doing real work (a missing sys.executable would still raise), it is just documented by a condition that can no longer occur — and a session reading it would conclude the doctor is protected against a Store-stub python on PATH, which is precisely what check_interpreter stopped guaranteeing.

Suggested: keep the #436-F3 circularity as history (past tense, it is the reason the flag exists), and state the live trigger — a sys.executable that is not a real interpreter path — as what the bypass survives today. notes/history.md § Machine setup already carries the correct account of the reversal; design_docs/001:526's version is provenance and should be left alone.

Also noted for #542: this is a fifth specimen of the class, and like notes/history.md:207 it is an assertion in prose about *behaviour*, not a runnable command shape — the command-position lane would not catch it.