parity: --info=mount/stats, --stats dir breakdown, --debug categories

--info=mount now prints rsync's mount-point skip line (matching rsync
3.4.1, which emits it for repeated -xx and drops the mount-point dir);
--info=stats enables the same block as --stats; -x is repeatable.
--stats counts traversed directories for the Number of files breakdown
even when no directory metadata is captured (-r without -t/-p).
--debug enables real output for flist/del/hash/deltasum/recv/filter/send
at their natural FastSync events (synthetic categories stay inert).

--stats and --debug rows keep their documented residual status.

src/shared/multiprocessing.c

@@ -50,6 +50,7 @@ PipelineContextSender* pipeline_context_sender_create(Config* config, Queue* que
   protocol_session_set_max_alloc(&context->allocation_session, config->max_alloc);
   context->dir_entries = NULL;
   context->dir_entries_mutex_init = false;
+  atomic_init(&context->dir_count, 0);
   context->delete_limit = false;
   int init = 0;
   if (config->use_metadata) {