spNextCntr coerced the 40-bit replay counter with `>>> 0`, so any counter
above FFFFFFFF lost its top byte after an accepted send: the live
10000AAAC8 came back as 00000AAAC9, and spCntrSyncPreset then stored the
broken value in the card preset - the RAM/Explore flows (ramIncrementCntr,
which is correct) inherited it.
- spNextCntr: 40-bit arithmetic (`% 0x10000000000`, wrap at FFFFFFFFFF
kept) instead of the 32-bit >>> 0 coercion plus slice(-10).
- spCntrAdjust (+/-): the same 40-bit wrap (an 11-digit value could be
produced at the maximum).
- tests: 10000AAAC8 -> 10000AAAC9, separator handling, FFFFFFFFF7 ->
FFFFFFFFF8, FFFFFFFFFFF -> 0000000000 wrap, out-of-range input clamps.
The server side (_increment_counter_hex, _ram_next_cntr, final_cntr) was
already exact. 653 frontend / 500 Python green; version 3.6.23;
sw simple-v296.
catarrh
991be7353b