v0.2.2

Patch release: robustness fix for out-of-space destinations. Wire-compatible
with 0.2.0 / 0.1.130.

Fixed

• Out-of-space destinations now fail fast and cleanly. The receiver checks
  free space against the file size before allocating and, if it won't fit,
  rejects with a clear "destination is out of space: N free, needs M" error
  instead of pre-allocating with fallocate (which could strand its partial
  reservation and fill the disk) and then dying mid-transfer with an opaque
  "connection reset by peer" on the sender. SSH mode no longer falls back to a
  doomed SFTP retry on such a rejection, and a failed fallocate now releases
  its partial reservation before falling back to a sparse file.