feat(stats): receiver-observed created/literal counters (protocol 2.28.0)

- PROTOCOL_VERSION 2.27.0 -> 2.28.0; STATUS_STATS gains literal_bytes and
  the created reg/dir/link/special counters (golden wire updated)
- receiver reports which destination entries it newly created, including
  implicitly-created parent directories below the logical transfer root, so
  Number of created files carries rsync's per-type breakdown
- Literal data is now exact for a delta transfer (receiver counts the literal
  fragments it stored)
- differential-tested vs rsync 3.4.1 for fresh-create, update and delta

src/shared/config.h

@@ -82,7 +82,7 @@ typedef struct {
 typedef enum SuperMode { SUPER_MODE_AUTO = 0, SUPER_MODE_ON = 1, SUPER_MODE_OFF = 2 } SuperMode;
 
 /* ===========================================================================
- * Config wire-field table (single source of truth for protocol 2.27.0).
+ * Config wire-field table (single source of truth for protocol 2.28.0).
  *
  * Every field below crosses the wire.  The table is the ONLY place a
  * serialized field is named: config.h expands CONFIG_WIRE_FIELDS() to declare
@@ -1006,7 +1006,20 @@ typedef struct Config {
  * the sender can print rsync's `deleting PATH` lines for a real deletion.  No
  * change to the fixed STATUS_STATS record itself; only a new trailing config
  * bool, which still requires the version bump for the strict lockstep. */
-#define PROTOCOL_VERSION "2.27.0"
+/* (8) --stats receiver-observed counters (protocol 2.28.0): the fixed
+ * STATUS_STATS record grows from three counters to eight.  The receiver now
+ * reports the bytes it literally stored (`literal_data`) and the count of
+ * destination entries it newly CREATED, split by type
+ * (reg/dir/link/special), so the sender can print rsync's exact
+ * `Number of created files: N (reg: X, dir: Y, link: Z, special: W)` line and
+ * an exact `Literal data` total even for delta transfers.  The config-frame
+ * LAYOUT is unchanged (no new config field), but the STATUS_STATS body grows,
+ * so a 2.27 peer that does not consume the five new fixed-width counters would
+ * desynchronize on the trailing would-delete path list; the strict
+ * same-version handshake (config_receive rejects a mismatched version before
+ * parsing anything else) keeps mixed deployments from ever reaching that
+ * state. */
+#define PROTOCOL_VERSION "2.28.0"
 #define DEFAULT_CHUNK_SIZE (10 * 1024 * 1024)
 /* Upper bound on total basis-dir entries (rsync caps --link-dest at 20). */
 #define MAX_BASIS_DIRS 64