lag parameter silently wraps around for values >= buffer size #379
Description
In plotymlag.py:7-26:
size = 10
lag = concore.tryparam("lag", 0)
# ...
ym[cur] = concore.read(1,"ym",init_simtime_ym)
ymt.append(np.array(ym[(cur-lag) % size]).T)
cur = (cur+1) % size
The circular buffer has a fixed size of 10, but lag is user-configurable via tryparam. If a user passes lag=15, the modulo wraps it to effectively lag=5, producing silently wrong data. There should be a validation: lag = min(lag, size-1) with a warning if the requested lag exceeds the buffer.