feat(parity): rsync 3.4.1 checksum/timeout/temp-dir/connectivity parity (#289 #295 #296)

#289 checksum/compression:
- -c/--checksum now implies the incremental content quick-check (without
  implying -t), so an unchanged file is skipped like rsync.
- --checksum-choice/--cc accepts xxh64/xxhash, xxh3, xxh128, md5 and auto;
  md4/sha1/none and the two-name form are rejected by name.
- --compress-choice/--zc rejects lz4/zlib/zlibx by name (zstd/none/auto kept).
- --checksum-seed=0 is randomized per transfer and sent on the wire.
- --skip-compress uses rsync 3.4.1's default suffix list; slash separators and
  dot-less suffixes are accepted.
- add --no-whole-file.

#295 timeouts/alloc/temp-dir:
- --timeout default 0 (disabled), --contimeout default 60; 0 disables both,
  plus --no-timeout/--no-contimeout.
- --max-alloc=0 means no allocation limit (was rejected).
- --temp-dir accepts any dir, requires it to exist, and falls back to a
  non-atomic copy on EXDEV instead of aborting.

#296 connectivity/daemon:
- -M/--remote-option is rejected for daemon/TCP destinations (SSH-only).
- --trust-sender clarified as receiver-local; server-path tests added.
- --stop-at accepts rsync's full date form (y-m-dTh:m etc.).

Adds unit and integration coverage; no wire-field change, PROTOCOL_VERSION stays
2.22.0.

tests/test_config.c

@@ -2899,13 +2899,14 @@ static void test_config_wire_receive_bounds() {
   /* BOOL: only 0/1 is a legal wire value. */
   EXPECT_TRUE(receive_hand_built_frame_rejected(write_frame_with_invalid_bool));
 
-  /* RAW_MAXALLOC: zero is rejected before it can become the session ceiling. */
+  /* RAW_MAXALLOC: zero is rsync's --max-alloc=0 "no limit" and round-trips;
+   * only the over-ceiling clamp is applied server-side. */
   Config* c = config_create();
   EXPECT_NOT_NULL(c);
   c->send_directory = str_dup("/src");
   c->receive_root_directory = str_dup("/dst");
   c->max_alloc = 0;
-  EXPECT_TRUE(roundtrip_config_rejected(c));
+  EXPECT_FALSE(roundtrip_config_rejected(c));
   config_delete(c);
 
   /* STR_MODULE: a name outside [A-Za-z0-9._-] is refused. */