fix: memoize Sparkline's derived rows/config (companion to #3, closes the rest of #2)

[DloomPlz]

Heads-up

#3 already stabilizes the registerSeries/unregisterSeries + registerVariant/unregisterVariant callbacks (nice work @seanryy — I hadn't seen it before opening this, sorry for the noise). This PR is now trimmed down to only the piece #3 doesn't cover, so the two merge cleanly together and fully close #2.

Problem

Sparkline rebuilds its derived props every render:

// React Compiler memoizes these against `data` / `color`.
const rows = data.map((v) => ({ v }))
const config = { v: { color } }

Without the compiler, rows gets a fresh identity each pass — and rows feeds useRevision's adjust-state-during-render, which then never stabilizes: every render bumps the revision, resets the entrance gate, and re-renders. Same class of bug as #2/#3, different entry point (this one triggers even after #3 lands).

Fix

Memoize rows/config with useMemo against data/color — exactly what the compiler emits for compiler-enabled projects, so no behavior change there. Registry JSON regenerated with npm run build.