Identify and implement top 5 code reduction

Identify top 5 opportunities to massively reduce the amount of code (lines of code) in any part of the repo: - Similar functionality that can be unified and reused - Code that has been valuable but no more - A front end component or a group of them duplicate another component/page functionality. Use the most modern and nice looking - etc. Now implement them :)

Top-5 code reduction: 4 cuts landed (API commit_row/reject_cleared/rows_out, web EditStatus gate, web test harnesses), 1 rejected on measurement (dirty-ladder, net -1). 108 files, net -305. Gates green; review lanes pass. PR #7827 queued in the merge lane.