The requirement marking function used test() then replace() on the
same global-flag regex. test() advances lastIndex, so replace() starts
from the wrong position and can miss the first match.
Replace with direct replace() + string comparison to detect changes.
Also drop unnecessary global flag from done-check patterns that only
need existence testing, and eliminate the duplicate regex construction
for the table pattern.
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
