metadata times: -U/--atimes, -N/--crtimes, --open-noatime, -O/-J

Capture+transmit source atime (pre-read stat; O_NOATIME sender guard) and birth
time (statx STATX_BTIME); receiver restores atime with mtime (crtime not settable
portably -> transmitted, explicitly not applied). --open-noatime is client-only.
-O/-J documented as accepted no-ops (FastSync never preserves dir/symlink times).
Wire: metadata frame gains atime/crtime val+sec+nsec; PROTOCOL_VERSION
2.11.0->2.12.0. Review fixes: gate atime capture to Linux (no epoch clobber on
non-Linux), close fd on fdopen failure, honest -O/-J status (Compat no-op).

src/shared/file_receive.c

@@ -1222,7 +1222,7 @@ File* receive_incremental_check(int fd, const Config* config, bool* skipped) {
         if (materialized && basis.content) {
           materialized->data = basis.content;
           basis.content = NULL;
-          materialized->metadata = file_metadata_create(&basis.st);
+          materialized->metadata = file_metadata_create(NULL, &basis.st, false, false);
           materialized->skip = true; /* receiver must not ack this as a data file */
           if (basis.type == BASIS_DEST_LINK) {
             materialized->basis_link = basis.basis_path;