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 :)

Measured the whole tree: no fold above ~100 lines remains that keeps documented semantics (306 redundant Python lines, all documented twins; 0 dead web/Python product symbols). Top 5 cuts (tests 870K, legacy runtime, Windows, types.ts generation, settings shells) are ADR/owner decisions, named in the report. No PR; no UI affected. Memory: used mem-31667, mem-31415, mem-18421; proposed 1 qa.