Each package ran the suite against a server backed by a full MemoryVFS, so
the servers' fallback paths were never entered. A second run reduces the
server's filesystem to the required operations while leaving the client under
test unchanged; it fails on #177 without the previous commit. Where a server
answers rather than shims — WebDAV 403 for PROPPATCH, FTP 502 and SFTP
SSH_FX_OP_UNSUPPORTED for rename — the run declares that instead of opting
out, which is the decision #179 revisits.
Fixes#181
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>