sphinx-fix

1✗ HARD-BROKEN BUILD — fix this first; the rest of the log is unreliable.2  signal: extension-error3    Extension error:4    Could not import extension myst_parser (exception: No module named 'markdown_it')5  The warning list below is incomplete until this is fixed.6 7Build: state=Finished  success=False  exit=28 9Partial findings (warning pass did not complete) (0):10  (none)11 12Unclassified (0) — no rule matched; resolve with the user, then file a skill-improvement ticket to add a rule:13 14Suppressed (0) — known-benign, not actionable:15 16Next: fix the hard-broken build above, then rebuild and re-run.17