test(delete): differential + timing regression tests for per-directory delete plans

- Compare --delete-during/--delete-delay final state against rsync 3.4.1.
- Force a mid-transfer failure through a byte-slicing proxy: --delete-during has
  removed the processed directory's extra, --delete-delay has not.
- Create a destination entry while the transfer is in flight: it survives
  --delete-delay's snapshot but is removed by --delete-after's fresh end scan.
- Cover the --delete-delay type-conflict case now matching rsync.

src/server/receiver.c

@@ -259,8 +259,7 @@ int receiver_process(Config* config, int file_descriptor, const ReceiverSink* si
    the whole transfer succeeded.  See receiver_process_pending() for how the -m
    receiver defers that commit until its disk writer has drained. */
 int receiver_process_pending(Config* config, int file_descriptor, const ReceiverSink* sink,
-                             DeleteManifest** pending_manifest,
-                             DeletePlanSession** pending_plans) {
+                             DeleteManifest** pending_manifest, DeletePlanSession** pending_plans) {
   Status status;
   if (!receive_status(file_descriptor, &status))
     return -1;

src/server/receiver_pipeline.c

@@ -167,8 +167,8 @@ int receive_thread(void* pipeline_context) {
 
   ReceiverSink sink = {
       receiver_enqueue_file, context, false, false, NULL, receiver_pipeline_note_delete_limit};
-  if (receiver_process_pending((Config*)config, file_descriptor, &sink,
-                               &context->deferred_manifest, &context->deferred_plans) != 0) {
+  if (receiver_process_pending((Config*)config, file_descriptor, &sink, &context->deferred_manifest,
+                               &context->deferred_plans) != 0) {
     receiver_thread_fail(context);
     protocol_session_unbind();
     return thrd_error;

src/server/server.c

@@ -966,8 +966,7 @@ void handler(int file_descriptor) {
          arrived; with the disk writer drained, commit the deferred removals.
          --delete-during already applied its plans on the receive thread. */
       if (context->deferred_plans) {
-        DeleteCommitResult deletion =
-            delete_plan_session_commit(context->deferred_plans, config);
+        DeleteCommitResult deletion = delete_plan_session_commit(context->deferred_plans, config);
         if (deletion == DELETE_COMMIT_ERROR) {
           transfer_ok = false;
         } else if (deletion == DELETE_COMMIT_LIMIT_REACHED) {