* fix: index or bound four small lookups (DOF selection, xref palette, QSELECT colours, log lines)
DOF scanned the selection list per slot; the xref palette scanned the xref list per INSERT; QSELECT parsed a possibly long layer name as a colour for every entity; and a log message could carry CR/LF or other control characters that started apparent extra records. Each now uses a set or map, a length bound, or escaping, with the same results for ordinary input.
* address review: trim colour text before length limit