mu 3.13.2

Keep verification useful as projects grow. The mu skill now defines
fast/slow gate responsibilities, scoped evidence reuse and routine test upkeep.

Upgrade with npm i -g @mu-crew/mu@3.13.2. New agent sessions load the updated
skill. Existing workers need updated briefs; no schema or extension change.

Changed

• Skill: fast/slow gates and routine test upkeep. Canonical
  test-health guidance assigns targeted
  worker/reviewer checks, equivalent gate records and one full merged-tree
  gate per batch. Milestones and budget crossings prioritise upkeep without
  a crew-wide barrier; auth/build isolation and required pre-push checks stay.
  mu's own gate commands remain unchanged pending review.
  Pilot baseline supplied for swaywardlock 90c3f1c: cold full 557.885 s,
  fast 216.140 s, slow 341.696 s (e2e 255.561 s, release 82.414 s);
  223 unit tests ~1 s, 64 e2e cases / 422 assertions, no skips. Converters
  initially cost ~28 s in fast: fast is not universally seconds. This is
  pilot timing, not an equivalent gate record for mu. A separate targeted
  vibrancy-wait follow-up preserved all seven assertions and reduced that
  case's mean from 3.350 s to 2.140 s; it does not establish a full-gate
  speedup or a solved budget.