Split MTEXT (or embedded-MTEXT) contents into DXF group 3 / group 1 pairs.
Spec order: full 250-char group-3 chunks first, then a final group 1 with the remainder (or the whole string when length ≤ 250).
Split MTEXT (or embedded-MTEXT) contents into DXF group 3 / group 1 pairs.
Spec order: full 250-char group-3 chunks first, then a final group 1 with the remainder (or the whole string when length ≤ 250).