fix(parity): rsync bwlimit units, --info categories, --ignore-errors deletion semantics

- --bwlimit: faithful port of rsync 3.4.1 parse_size_arg (default KiB/s,
  binary K/M/G/T/P, decimal KB/MB, KiB/MiB, decimals, 0 = unlimited, 512-byte
  floor, (size+512)/1024 quantization).  Unit tests + docs.
- --info: wire del/remove/name/flist/nonreg/progress to real FastSync events in
  rsync's line format (deleting PATH, sender removed NAME, name lines,
  'sending incremental file list', skipping non-regular file "NAME"); name no
  longer aliases copy; --info=progress drives the progress path and report_stats.
- --ignore-errors: match rsync's default -- a source I/O error skips deletion
  unless --ignore-errors, while the readable tree still transfers and the run
  exits 23.  Covers all delete timings and both send paths.

src/shared/multiprocessing.h

@@ -83,6 +83,11 @@ typedef struct {
      thread transmits the root plan before any data and the remaining plans
      alongside the chunks.  Set once before the worker threads start. */
   DeletePlanSender* delete_plans;
+  /* A scan I/O error without --ignore-errors suppressed deletion: the prebuilt
+     keep-set/plans were dropped, and the streaming scanner must not build a
+     fresh manifest or re-send the per-directory plans.  Set once before the
+     worker threads start. */
+  bool delete_suppressed;
   mtx_t mutex_progress;
   int total_files;
   unsigned long long progress_bytes;