feat(parity): real --info=del deletion lines + rsync throttle pacing

- Wire: config frame gains report_deletes (protocol 2.26.0 -> 2.27.0); the
  receiver lists actually-removed paths in the STATUS_STATS path list, so the
  sender prints rsync's `deleting PATH` / `*deleting   PATH` lines for a real
  --delete run (and -i/out-format).  Observers threaded through the manifest,
  missing-args and per-directory delete engines; golden wire len/hash updated.
- bwlimit: throttle now paces like rsync 3.4.1 -- ~100ms burst capacity and the
  sleep is no longer credited as refill, so 4 MiB at 1024/2048 KiB/s matches
  rsync within ~4% (was ~2x too fast).

src/server/receiver_pipeline.c

@@ -31,6 +31,7 @@ PipelineContextReceiver* pipeline_context_receiver_create(Config* config, Queue*
   context->delete_limit_reached = false;
   memset(&context->stats, 0, sizeof(context->stats));
   context->would_delete = NULL;
+  context->deleted_paths = NULL;
   atomic_init(&context->cancelled, false);
   int init = 0;
   if (mtx_init(&context->mutex, mtx_plain) != thrd_success)
@@ -46,6 +47,9 @@ PipelineContextReceiver* pipeline_context_receiver_create(Config* config, Queue*
   context->would_delete = array_list_create(free);
   if (!context->would_delete)
     goto fail;
+  context->deleted_paths = array_list_create(free);
+  if (!context->deleted_paths)
+    goto fail;
   return context;
 
 fail:
@@ -71,6 +75,8 @@ void pipeline_context_receiver_destroy(PipelineContextReceiver* context) {
   dir_time_list_free(&context->dir_times);
   if (context->would_delete)
     array_list_delete(context->would_delete);
+  if (context->deleted_paths)
+    array_list_delete(context->deleted_paths);
   mtx_destroy(&context->mutex);
   cnd_destroy(&context->condition_not_full);
   cnd_destroy(&context->condition_not_empty);
@@ -184,7 +190,8 @@ int receive_thread(void* pipeline_context) {
                        NULL,
                        receiver_pipeline_note_delete_limit,
                        &context->stats,
-                       context->would_delete};
+                       context->would_delete,
+                       context->deleted_paths};
   if (receiver_process_pending((Config*)config, file_descriptor, &sink, &context->deferred_manifest,
                                &context->deferred_plans) != 0) {
     receiver_thread_fail(context);