trade_notional.py — max-amount gate (@boundary place_order@1)

@boundary("place_order", kind="tool")
def place_order(symbol, quantity, *, side="sell"):
    notional = quantity * SHARE_PRICE_CENTS
    if _mode == "gated" and notional > MAX_ORDER_NOTIONAL_CENTS:
        return {"status": "blocked", "blocked": True, ...}

    return {"status": "filled", ...}  # ungated: $190k executes
★ Cut-point: Only this boundary runs live with the fix.