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_stop.c

@@ -74,8 +74,6 @@ static void test_stop_at_parse_now_plus() {
 static void test_stop_at_parse_invalid() {
   time_t now = 1700000000;
   time_t deadline = 0;
-  EXPECT_FALSE(stop_parse_at_time("12", now, &deadline));
-  EXPECT_FALSE(stop_parse_at_time("12:3", now, &deadline));
   EXPECT_FALSE(stop_parse_at_time("1234", now, &deadline));
   EXPECT_FALSE(stop_parse_at_time("12:30:5", now, &deadline));
   EXPECT_FALSE(stop_parse_at_time("12:30:5x", now, &deadline));
@@ -100,6 +98,54 @@ static void test_stop_at_parse_invalid() {
   EXPECT_FALSE(stop_parse_at_time(NULL, now, &deadline));
 }
 
+/* rsync's flexible date form for --stop-at (y-m-dTh:m, with / separators and
+ * abbreviable fields). */
+static void test_stop_at_parse_date_forms() {
+  time_t now = 1700000000;
+  time_t deadline = 0;
+  struct tm t;
+
+  EXPECT_TRUE(stop_parse_at_time("2030-12-31T23:59", now, &deadline));
+  EXPECT_NOT_NULL(localtime_r(&deadline, &t));
+  EXPECT_EQ_INT(t.tm_year + 1900, 2030);
+  EXPECT_EQ_INT(t.tm_mon + 1, 12);
+  EXPECT_EQ_INT(t.tm_mday, 31);
+  EXPECT_EQ_INT(t.tm_hour, 23);
+  EXPECT_EQ_INT(t.tm_min, 59);
+
+  EXPECT_TRUE(stop_parse_at_time("2030/12/31T23:59", now, &deadline));
+  EXPECT_NOT_NULL(localtime_r(&deadline, &t));
+  EXPECT_EQ_INT(t.tm_year + 1900, 2030);
+  EXPECT_EQ_INT(t.tm_mon + 1, 12);
+  EXPECT_EQ_INT(t.tm_mday, 31);
+
+  EXPECT_TRUE(stop_parse_at_time("2030-12-31", now, &deadline));
+  EXPECT_NOT_NULL(localtime_r(&deadline, &t));
+  EXPECT_EQ_INT(t.tm_year + 1900, 2030);
+  EXPECT_EQ_INT(t.tm_hour, 0);
+  EXPECT_EQ_INT(t.tm_min, 0);
+
+  /* Partial forms resolve to the next matching point in the future. */
+  EXPECT_TRUE(stop_parse_at_time(":59", now, &deadline));
+  EXPECT_TRUE(deadline > now);
+  EXPECT_NOT_NULL(localtime_r(&deadline, &t));
+  EXPECT_EQ_INT(t.tm_min, 59);
+
+  EXPECT_TRUE(stop_parse_at_time("1-30", now, &deadline));
+  EXPECT_TRUE(deadline > now);
+  EXPECT_NOT_NULL(localtime_r(&deadline, &t));
+  EXPECT_EQ_INT(t.tm_mon + 1, 1);
+  EXPECT_EQ_INT(t.tm_mday, 30);
+
+  EXPECT_TRUE(stop_parse_at_time("1", now, &deadline));
+  EXPECT_TRUE(deadline > now);
+  EXPECT_NOT_NULL(localtime_r(&deadline, &t));
+  EXPECT_EQ_INT(t.tm_mday, 1);
+
+  /* Seconds are not part of rsync's date form. */
+  EXPECT_FALSE(stop_parse_at_time("2030-12-31T23:59:59", now, &deadline));
+}
+
 static void test_stop_deadline_latency() {
   struct timespec now;
   EXPECT_EQ_INT(clock_gettime(CLOCK_MONOTONIC, &now), 0);
@@ -145,6 +191,7 @@ void test_stop(void) {
   test_stop_after_parse_invalid();
   test_stop_at_parse_hhmm();
   test_stop_at_parse_now_plus();
+  test_stop_at_parse_date_forms();
   test_stop_at_parse_invalid();
   test_stop_deadline_latency();
 }