v2.202.0 — E150: a rebase needs a real majority; retime rounding is the same window

Fixed

• A timecode rebase needs a majority of ALL the source's cuts. The rule
  measured its majority over the cuts whose windows differed, so on a real
  reel two shifted cuts out of fifty-four became that source's base and
  turned fifty-two UNCHANGED cuts into false trims (a control with a free
  floor). The majority is now over every paired cut of the source (at least
  two, and more than half). On that reel: 187 → 237 of 335 cuts retained; the
  reels where a rebase is real keep it.
• One source frame of rounding on a retimed pair is the same window.
  Premiere's exact 80% and Resolve's keyframe slope (0.79999, frame-quantized
  seconds) land one frame apart (41923 vs 41922). On a pair where either side
  is retimed a source edge within srcTolerance (default 1 frame) compares
  equal; a 100% pair keeps the exact compare; two frames is still a trim.