- 0001: remove NS_AX_TEXT_CAP (100K char cap), add lineStartOffsets/
lineCount ivars and method declarations to nsterm.h
- 0002: add lineForAXIndex:/rangeForLine: O(log L) helpers, build line
index in ensureTextCache, replace O(L) line scanning in
accessibilityInsertionPointLineNumber/accessibilityLineForIndex/
accessibilityRangeForLine, free index in invalidateTextCache/dealloc
- 0009 deleted (folded into 0001+0002)
- README.txt: remove NS_AX_TEXT_CAP references, update known
limitations, stress test threshold 50K lines