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 :)

No PR: five recon agents and five scanners (jscpd, knip, vulture, AST near-dup, route cross-check) measured duplication at 0.02% of 647k source lines, 0 in 596k test lines, no dead file/type/route; migrations already collapsed. Top 5 candidates total <60 lines, 3 deliberate copies. Report has the evidence; no UI surface affected.