fix(delete): match rsync deletion semantics (#290)

- Scope the --delete extras walk to directories synchronized by the
  transfer: add a synchronized-directory section to the delete manifest
  (protocol 2.23.0) so --files-from subsets no longer delete untransmitted
  paths outside listed directory subtrees (data-loss fix).
- Separate --max-size/--min-size prune protection from --delete-excluded so
  size-pruned source mirrors survive (rsync parity).
- Unlink extraneous destination symlinks instead of skipping them.
- Make --max-delete partial (delete up to N, skip the rest) and exit 25;
  accept negative values as unlimited.
- Draw --delete-missing-args deletions from the shared --max-delete budget.
- Honor --force during --delay-updates publication.

Add unit and integration regression tests; update the pinned config wire
golden and version strings for the 2.23.0 manifest/status additions.

tests/integration/test_fault_injection.py

@@ -36,7 +36,7 @@ from common import (  # noqa: E402
     verify_transfer,
 )
 
-PROTOCOL_VERSION = b"2.22.0"
+PROTOCOL_VERSION = b"2.23.0"
 STATUS_MANIFEST = 5
 STATUS_OK = 0