Reduce codebase by implementing top five 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 :)

Implemented the top-5 reductions (−497 net lines, 94 files): 62 web suites onto the shared auth/api mocks (helper gained spies), retired 5 console addresses nothing emits, jaahd vocabulary snapshot publisher and a tools inline selftest removed, shortSha folded. Quick gate green on every commit; code + security review lanes pass. PR #7441 queued in the merge lane. Deferred with evidence: legacy webhook auth (6 live triggers still use it). Memory: used mem-31005; proposed none.