[TheGreatAxios]

Closes CL-9432

AnimatedNumber. fromRef was only updated when a count finished, so a new value arriving mid-count jumped back to the previous target before animating. Each frame now writes the interpolated number to fromRef, so the next count starts from what is on screen.

ThemeProvider. The initial state read localStorage and matchMedia during render, so a client with a stored preference or a dark OS rendered different text than the server and hydration failed. Preference now starts from the defaultMode/defaultPreset fallback and system dark starts false, matching the server; the existing mount effects read storage and matchMedia afterwards. The unused readSystemPrefersDark helper is removed.

Tests: a value change mid-count continues from the displayed number (fake requestAnimationFrame/performance.now); renderToString then hydrateRoot with a stored dark preference reports no recoverable errors and ends on dark/dark. Both fail on the previous code. No public API change.