C2: --force is deletion authority (an incoming regular file may remove a
non-empty destination directory tree, and --delete-missing-args may
remove a non-empty directory mirror), but it was not masked by the
operator --allow-delete policy. The handler now clears
config->force_delete unless --allow-delete was given, exactly like
--delete and --delete-missing-args.
C3: a standalone TCP / --stdio server running as root defaulted to
SUPER_MODE_AUTO, so an untrusted client --devices/--write-devices/
--super could make it create device nodes, write raw devices, or apply
client-chosen ownership. A privileged standalone receiver now forces
SUPER_MODE_OFF unless the operator opts in with the new server-only
--allow-super flag. Non-root receivers are unchanged, and the daemon
path keeps its per-module `client owner = yes` gate. --allow-super is
rejected with --no-super or --daemon.
C6: tls_client_identity_allowed now rejects a CN whose reported length
reached the buffer bound, so a truncated over-long CN cannot be matched
by a required --client-cn prefix.
Tests: an integration regression proving --force cannot replace a
destination directory without --allow-delete; standalone-default tests
for --copy-as refusal and (root-only) skipped device creation; a CLI
unit test for the new flag. The integration shared_server fixture opts
in with --allow-super so the existing root-only ownership/device/copy-as
tests continue to exercise the opted-in configuration. README and
RSYNC_COMPAT document the flag and the force/delete gating.