fix: trigger fires require a fresh cross — stale breaks after a blind window are chases

SNXX 2026-07-21: 18s after a mid-morning restart the fast path bought a
15-minute-old break +1.6% above the trigger — fires() only checked
price >= trigger, so any blind window (boot, halt, feed outage) fired
instantly on already-extended moves. A trigger now fires only if the live
price was seen BELOW the trigger since arming (a real cross), with a
small at-the-break tolerance (TRIGGER_FRESH_CROSS_TOL, default 1.5%)
so a fast break between ticks still fires; beyond it the name must pull
back below the level and re-cross. Gap-through runners stay covered by
the slow marketable path.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

run_live_paper.py

@@ -450,6 +450,7 @@ def build_runtime(args: argparse.Namespace) -> dict:
         min_range_pct=float(os.environ.get("TRIGGER_MIN_RANGE_PCT", "0.004")),
         min_dollar_vol=float(os.environ.get("TRIGGER_MIN_DOLLAR_VOL", "0")),
         max_price_age_s=float(os.environ.get("TRIGGER_PRICE_MAX_AGE", "12")),
+        fresh_cross_tol=float(os.environ.get("TRIGGER_FRESH_CROSS_TOL", "0.015")),
     )
 
     return {