Add hunt-side live ETU recovery so a card already at a non-default F/D
(e.g. Samsung F=512/D=32 -> 16 CLK/bit) can be decoded without a 372-rate
ATR, and bound the all-0xFF hunt so an idle/unsyncable line can never loop
forever.
- _recover_etu_in_hunt(): measure the live ETU from DATA edges while still
in FIND START, then re-derive clock_skip; reuses _confirm_etu validation.
- _atr_hunt_failure_action(): pure recover/retry/resume_data decision, with
ATR_HUNT_ETU_ATTEMPTS=3 / ATR_HUNT_IDLE_RESETS=3 / ATR_HUNT_FAIL_LIMIT=12.
- Persistent counters reset only on a successful ATR parse (not RST re-arm),
so RST-cycling phones cannot starve the escape.
- 8 new unit tests (55 total).
Validated on the full trace suite (test_8 56/0/OK, test_7 65/0/OK, xiaomi
640, xiaomi_cold 473, 4gmodem 327, A55 407/395, S21p 399/375, target S21p
369; 0 CONCAT, RESULT: OK) with no regressions.
Трошин Антон Валерьевич
bca1b85b94