v0.5.1

v0.5.1 — surface OB mitigation flags + per-OB touch_count

Additive schema change to the order-block primitive: every OB now ships
with three freshness signals so consumers can pick their criterion:

  - mitigated_wick : later bar's wick traversed the zone (lib loose)
  - mitigated_close: later bar's body broke past (lib strict)
  - touch_count    : number of distinct touch events (trader-eye)

The two lib flags fire only on INVALIDATING breaks (price went past
the zone in the wrong direction). touch_count fires on ANY range
intersection — captures "price visited this level" without requiring
a full break.

Cost: one extra smc.ob() call (mitigation_close) + a numpy edge-count
per OB (touch_count). Sub-ms total. OB cap raised 20 -> 40 since we no
longer pre-filter.

Breaking for FE renderers that assumed every emitted OB was live.
Quanthex consumer updated to gate on wick + use touch_count for graded
weighting (0 fresh = full, 1 = half, 2+ = re-emit as S/R primitive).

323 unit tests pass.