Closes#3445.
New ui/relative-time/RelativeTime — takes a UTC epoch-ms instant, not
a precomputed age, and re-renders itself on a 1s interval so a tab
left open doesn't silently show a frozen 'fresh (5s ago)' hours
later. Pauses while the document is hidden, resyncs immediately on
becoming visible again.
StatusChip's label widened from string to ComponentChildren so a
chip can embed the live ticker (a plain string couldn't carry it).
HivesPage's freshness column now derives the age from last_seen_unix
client-side via RelativeTime instead of rendering the once-computed
age_seconds from the API response.
Verified: tsc clean, build succeeds, screenshotted the components
page (ticking observed advancing within one virtual-time-budget
window) and the hives page (fresh/stale/never-reported all render
correctly).
a5ef31ed8b