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 :)

Measured the tree (jscpd/ts-prune/import graph: <0.1% dup, 0 dead files), so no massive cut exists; collapsed the five real clusters: compliance api mock, web test fixtures, agent-route task guard, toolbox git env, Python test arranges. Net −220 lines, 57 files, behaviour unchanged; quick gate, 1750 web + 2890 API (live Postgres) tests green; 3 blind lanes PASS. PR #7716 queued to the merge lane. No UI surface affected. Memory: used mem-32769; proposed none.