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 :)

Five reductions shipped in PR #7870 (queued to the merge lane): Agent index table folded onto the command center's METRIC_COLUMNS/MetricHead/MetricValue (Compare row heads too), apiFetch alias gone, 32 dead types.ts exports un-exported, blind-review security tier on REVIEW_PERSONAS; a task_sections fold reverted (import cycle, mem-36360). Quick gate green, 114 vitest + 50 pytest passed, visual check on both surfaces done and good. Net −16 lines: every census shows the repo at its dedup floor; the four 50–300-line levers left are compatibility seams needing a product/deploy decision (identity dual-write contraction foremost), named as deferred in the report and PR body. Memory: used mem-25288, mem-32882; proposed 1 gotcha.