2026-08-27 - hardening the probe for hardware: the extent blind spot was half-closed

Asked to harden the active probe before the hardware run. The two axes named - the size record (binary-search a size argument to derive exact structure sizes) and the "wrote-0 vs untouched" extent fix - were already built by concurrent work: the poison-fill dump, obs_report_written with changed/untouched runs, obs_report_size, and check_query_size_ladder all present, and both records documented in OUTPUT.md.

The residual: the dump was moved onto the poison basis and the verdict counter beside it was left on the old non-zero one. Observed live on the host - the same call reporting extent 256 in its dump and pass|0x11 (17) in its verdict. On hardware that mismatch fails the other way: a call writing a real structure with a zeroed trailing field gets "the call succeeded and wrote nothing", a false failure contradicting its own dump. Fixed to count changed-from-poison; the call now reports pass|0x100, matching. verify: ok, 24 gates. (D204)

Surprise worth noting: the decision index had drifted (203 body entries, stale index) from the concurrent selfish split and D199-D203 - regenerating brought it current before D204 landed.