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 five folds (IAM tolerant-call seam, billing dialog guard, shared launch-gate scaffold, web Forge/SortDir/Page re-declarations): 15 repeated mechanisms now have 4 homes; line count roughly flat. A seven-tool census shows no dead code or large clone remains, so the "massively" criterion is too strong for this tree (report). Quick gate, changed-area API/web suites, two blind review lanes green. PR #7940 queued in the merge lane.