Reduce repository code by implementing top five

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 five code-reduction consolidations shipped (jaahd leaf helpers, web source, web tests, API census+backoff, infra/tools helpers): 94 files, net −284 lines, behaviour kept. PR #7471 merged by the lane; Jaah Deploy succeeded. "Massive" cuts do not exist in this tree (prior dedup tasks took them); flagged in report. Filed draft 11736 (14 orphaned test files). Memory: used mem-31277; proposed none.