The CIR estimator's dominant_tap_ratio measured a single grid bin, but on the
3x super-resolved ISTA grid a single physical tap leaks across ~3 adjacent
bins — so the ratio under-counted the dominant tap and sat far below the
per-tier floors (HT20 0.158<0.30, HT40 0.133<0.35, HE20 0.102<0.40), forcing
the 3-tap recovery + 40MHz-ToF tests to be #[ignore]d.
Fix (data-backed via a lambda sweep): (1) compute dominant_tap_ratio over a
+/-1-bin window around the peak — the physical tap's true footprint; (2) tune
L1 lambda for sparse multipath (HT20 .05->.08, HT40 .03->.08, HE20 .03->.18).
Result: ratios 0.367/0.406/0.474, comfortably above floors with all 3 taps
preserved. Un-ignores should_recover_3tap_channel_{ht20,ht40,he20} and
should_return_tof_at_40mhz. signal crate: 470 pass / 0 fail; change isolated
to CIR (no external consumers). The rms-delay-spread test stays ignored with a
re-scoped note (far-tap robustness is separate remaining work).
Co-Authored-By: claude-flow <ruv@ruv.net>
d55c4d4b65