* perf(engine): replace linear scans that made document-sized inputs quadratic
enum_of re-classified the whole string for every character; widget names,
comment mentions and devcompare's common siblings each searched a growing
Vec; data.fill's export names and codegen's class names retried every
suffix from 2 against a list, cubic in the number of copies of one name;
and a batch rename template had no length cap although it is expanded
again for every match.
* address review: report the pattern in its own length error