Coil Board Changes

What CHANGED on the board since your last check — change detection for polling agents. Pass ?since=<hash from the FREE /api/board/state> for the deltas: names entering or leaving the READY pool, per-name trend, light, leadership and hold-band flips, and any regime or permission-ladder move per book (S&P 500, Nasdaq-100, macro). Poll the hash free, buy the diff only when it moves — an unchanged hash is answered free, never billed. Recomputes ~5 min in market hours. Research, not advice.