- handle_pps(): flag the first post-PPS character; _read_byte_clk() re-measures
the CLK period there and accounts the measurement's 16 edges. The Alcor
reader upclocks 4.0 -> 4.8 MHz at PPS (FI/DI still 512/32), so the ATR
measurement was stale: 64 vs 53.33 samples/ETU, no post-PPS APDU framed.
- _wait_clk_rising(): project to the n-th edge (skip to target - half a
period, take one edge) instead of "skip n-2 cycles + 2 edges", which lost
~1 edge per call on fractional periods and slid the samples ~0.5 ETU early
by the parity bit. xiaomi 7698 -> 2, 4gmodem 7218 -> 0, S21p_sim2 394 -> 0
CHKSUM lines (previously misread as dirty-wire noise).
- CONCAT gate: EMBEDDED_CLA excludes the structural 0x4x/0x5x classes (payload
false hit on the Alcor secured packet); mirrored in tools/vs_reader.py and
covered by a new vector in tests/test_gsmtap.py.
- tools/capture_baseline.sh: add the alcor_reader_sample fixture; baseline
regenerated (APDU counts and RESULT: OK unchanged everywhere, 0 CONCAT).
- 75/75 unit tests. README/AGENTS updated.