Even with primitive useEffect deps, TanStack Query or React concurrent
rendering can cause onMetrics to fire with identical values mid-render-cycle.
Add a ref-based equality check in Dashboard.onMetrics: if all five metric
values are unchanged, skip setMetricsById entirely — no state update, no
Dashboard re-render, loop terminates.
Also fixes vi.fn<TFunction>() typing in server-workspace-rows.test.tsx to
satisfy tsc (Vitest 4 single-type-arg signature).
3b88a41afd