v0.4.1 — self-update divergence fix

[0.4.1] - 2026-06-13

Patch. No breaking changes.

Fixed

• self-update now diagnoses why a fast-forward can't happen. It used to
  run git pull --ff-only and, on failure, always blamed local commits or
  changes — misleading after an upstream force-push (e.g. a squash), which left
  a checkout stuck on a raw "Not possible to fast-forward" git error. It now
  fetches and classifies the state, then prints the right recovery:
  up-to-date (no-op), behind (fast-forwards), uncommitted changes
  (git checkout -- .), local commits ahead (git reset --hard <upstream>),
  or diverged history from a force-push (git reset --hard <upstream>, noting
  the registry in ~/.config/dctl is untouched).