init_path: optimizing pathdef.m building (courtesy of claude). Brings down matlab startup by ~50x. - heinmatt
added trig channel fallback to 0 following error or stop
added TMS parameter screen vi
heinmatt: removed case of ps_id = 3 that would also evoke full field visual flow halts
Set it back to a simpler option. User just needs to feed a vector of seed ROIs indices. Common seeds are used across siteIDs. TK