The push-convergence path synthesizes PR titles as '<kind>: converged
release' where kind comes from version_convergence.highest_warranted_bump
(minor|patch). semver_bump then re-derived the kind from the TITLE TEXT
and 'minor:' matched nothing → patch. Every feature tranche downgraded:
T18/T19/T20 feat ranges bumped 0.66.77-83 instead of 0.67.0. Fixed:
MINOR_PREFIX_RE carries the convergence decision through. Held-out
proves minor-title→0.67.0 and patch-title→0.67.1 (no accidental
re-minor). This is the 0.66.x problem the mandate named, root-caused.