v0.6.3

• Approved snapshots carry a short digest of the reviewed text in their name (<stem>-rev<N>-<digest>.md), so two
  sessions approving the same plan name no longer block each other (#52). A name that is already taken gets a short
  random tag; plan-mode never reuses, follows or replaces an existing file there, and long plan names are trimmed to
  fit one 255-byte file name.