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/delete_plan.c

@@ -412,6 +412,11 @@ struct DeletePlanSession {
   bool dry_run;
   size_t max_delete;
   size_t deleted;
+  /* Removals charged against --max-delete.  In --delete-delay mode a path is
+     planned (and the budget consumed) while scanning, but `deleted` advances
+     only when the commit actually unlinks it, so an entry that survives the
+     commit (a directory refilled mid-transfer -> ENOTEMPTY) is not reported. */
+  size_t planned;
   size_t skipped;
   bool limit_hit;
   bool limit_logged;
@@ -565,7 +570,7 @@ static bool build_plan_skips(const Config* config, const DeletePlanSession* sess
 }
 
 static bool budget_available(const DeletePlanSession* session) {
-  return session->deleted < session->max_delete;
+  return session->planned < session->max_delete;
 }
 
 static void note_skipped(DeletePlanSession* session) {
@@ -579,7 +584,9 @@ static void log_deleted(const char* rel) {
   free(escaped);
 }
 
-/* Append a snapshot path for --delete-delay. */
+/* Append a snapshot path for --delete-delay.  The budget is charged here, but
+ * `deleted` is not: the path counts only once apply_deferred_path truly
+ * unlinks it. */
 static bool defer_add(DeletePlanSession* session, const char* rel) {
   char* copy = str_dup(rel);
   if (!copy)
@@ -588,7 +595,7 @@ static bool defer_add(DeletePlanSession* session, const char* rel) {
     free(copy);
     return false;
   }
-  session->deleted++;
+  session->planned++;
   return true;
 }
 
@@ -633,6 +640,7 @@ static bool process_extra_dir(int dirfd, const char* name, const char* child_rel
   }
   if (unlinkat(dirfd, name, AT_REMOVEDIR) == 0) {
     session->deleted++;
+    session->planned++;
     log_deleted(child_rel);
     *removed = true;
     return true;
@@ -657,6 +665,7 @@ static bool process_extra_file(int dirfd, const char* name, const char* child_re
   }
   if (unlinkat(dirfd, name, 0) == 0) {
     session->deleted++;
+    session->planned++;
     log_deleted(child_rel);
   } else if (errno != ENOENT) {
     return false;
@@ -768,13 +777,14 @@ static bool apply_missing(DeletePlanSession* session, const Config* config) {
     return true;
   DeleteManifest manifest = {
       .keeps = NULL, .protected = NULL, .missing = session->missing, .dirs = NULL};
-  size_t remaining = budget_available(session) ? session->max_delete - session->deleted : 0;
+  size_t remaining = budget_available(session) ? session->max_delete - session->planned : 0;
   size_t deleted = 0;
   size_t skipped = 0;
   bool limit = false;
   bool ok = manifest_delete_missing_args_limited(config, &manifest, remaining, &deleted, &skipped,
                                                  &limit);
   session->deleted += deleted;
+  session->planned += deleted;
   session->skipped += skipped;
   if (limit)
     session->limit_hit = true;
@@ -839,7 +849,6 @@ int delete_plan_session_receive(DeletePlanSession* session, const Config* config
 /* Apply one snapshotted --delete-delay path (post-order: children precede their
  * parent directory). */
 static bool apply_deferred_path(DeletePlanSession* session, const Config* config, const char* rel) {
-  (void)session;
   char* full = path_cat(config->receive_root_directory, rel);
   if (!full)
     return false;
@@ -863,8 +872,10 @@ static bool apply_deferred_path(DeletePlanSession* session, const Config* config
   else
     rc = unlinkat(parent_fd, leaf, 0);
   bool ok = rc == 0 || errno == ENOENT || errno == ENOTEMPTY || errno == EEXIST;
-  if (rc == 0)
+  if (rc == 0) {
+    session->deleted++;
     log_deleted(rel);
+  }
   close(parent_fd);
   free(leaf);
   return ok;