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 :)

Shipped the five largest real reductions (net −281 lines, 54 files) in PR #7405, merge lane queued: one home for the fleet account settings (194-line twin deleted; CE/dev nodes ship the canonical), RowEnvelope for five sealing triplets, thin API wrappers dropped, two readers onto useApiRead, duplicate test helpers hoisted. Evidence shows no massive cut exists (0.7% duplication, 21 dead lines repo-wide). Quick gate pass; review lanes pass; visual check done, Access tab and signup render unchanged. Memory: used mem-31055; proposed none.