Langroid: SQLChatAgent _validate_query blocklist misses pg_read_file family enabling arbitrary file read

SummarySQLChatAgent in langroid ships a validatequery defense-in-depth layerwhose DANGEROUSSQLPATTERNS regex blocklist enumerates dangerous SQLprimitives by specific function name. The list misses the canonicalPostgreSQL filesystem-disclosure family pgreadfile, pgstatfile,pglslogdir, pglswaldir,...