Reduce repository code volume through refactoring 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 :)

Five code-volume cuts (−828/+173, 67 files): dead web exports, two uncalled API routes, MissingRecordState→DetailStatus, FactsGrid/KeyValueList and CodeBlock adoption. Tree was at its exact-clone floor; larger items are operator decisions (named in report). Quick gate green; review lanes pass; visual check done (not-found pages at 1280/448px clean). PR #7567 queued in the merge lane. Memory: used mem-32704; proposed 2 gotchas.