Find and implement five code reduction opportunities

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 code-reduction units shipped in PR #7477 (queued to the merge lane): test-only production functions deleted; API and console test clones onto shared homes. 85 files, net about −420 lines. Quick gate green, every changed-area suite passing. Two further units were built, measured, and reverted (EmptyState migration, notify factory): no reduction. Repo is already single-homed at production level; no massive win exists safely.