fix(parity): actual-removal delete-delay counts, rsync-accurate stats/progress/%C

- --delete-delay: count/track only entries actually removed; a directory
  refilled before commit (ENOTEMPTY) no longer inflates Number of deleted
  files or the --max-delete budget (unit + integration + rsync differential).
- --stats: per-type Number of files breakdown; only stored regular files
  count as transferred; transferred/literal byte totals and Total file size
  (symlink target lengths) now match rsync for whole-file transfers.
- --progress: print the leading ./ root line and include the root entry in
  the to-chk denominator (single-file output byte-identical to rsync).
- --out-format %C: use the selected transfer checksum and render every
  algorithm exactly like rsync; checksum_digest_file gains md4/sha1/none.
  Reclassify --out-format to Divergent (protocol-specific %b/delta-%c).
- Docs: RSYNC_COMPAT tally 107/25/24, HANDOFF update. No wire change.

src/shared/multiprocessing.c

@@ -42,6 +42,7 @@ PipelineContextSender* pipeline_context_sender_create(Config* config, Queue* que
   context->total_files = 0;
   context->progress_bytes = 0;
   context->total_bytes = 0;
+  memset(&context->stats, 0, sizeof(context->stats));
   context->sender_done = false;
   atomic_init(&context->cancelled, false);
   protocol_session_init(&context->allocation_session, -1, -1);