Identify and implement top five 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 :)

Five single-home folds shipped, net −81 lines on a tree at its dedup floor: top-up on AmountDialog, parametrised tenancy key tests, shared test fixtures, one UTC stamp per side, forges.quote_segment. Quick gate green, blind review+security+verifier passed, visual check done (clean at 1280/448). PR #7564 queued to the merge lane. Memory: used mem-32704, mem-32217; proposed none.