fix: memoize context values to prevent infinite re-renders

[mvanhorn]

Summary

• Memoize ActiveThemeProvider context value with useMemo to prevent new object references on every render
• Memoize BlockViewerProvider context value with useMemo for the same reason
• Consumers now only re-render when the actual context values change

Why this matters

#59 reports infinite re-renders on the home page. The reporter traced it via React Profiler to a Context Provider creating new object references per render - this is the classic unmemoized context value pattern.

ActiveThemeProvider wraps the entire app in the root layout (app/layout.tsx), so every render of that provider triggers a re-render of every consumer in the tree. Wrapping the value in useMemo maintains referential equality and breaks the render loop.

Changes

• apps/www/components/active-theme.tsx - wrap { activeTheme, setActiveTheme } in useMemo
• apps/www/components/block-viewer.tsx - wrap context value object in React.useMemo

Testing

• pnpm run typecheck passes
• Build and lint failures are pre-existing on main (unrelated /radio page data collection error)

Fixes #59

This contribution was developed with AI assistance (Claude Code).

[vercel]

@mvanhorn is attempting to deploy a commit to the ElevenLabs Team on Vercel.

A member of the Team first needs to authorize it.

[mvanhorn]

@kraenhansen - friendly ping. Approved a while back, no merge activity - let me know if anything else is needed.

[kraenhansen]

@mvanhorn can I ask you to rebase and fix the prettier failure? 👍

[mvanhorn]

Rebased onto main and ran prettier in 83e9246. format:check passes locally. (The pnpm lint failure is pre-existing on main - next lint errors with 'Invalid project directory' there too, unrelated to this PR.)