feat(core): support React 19 browser() in BrowserOnly

[sanjaiyan-dev]

Pre-flight checklist

• I have read the Contributing Guidelines on pull requests.
• If this is a code change: I have written unit tests and/or added dogfooding pages to fully verify the new behavior.
• If this is a new API or substantial change: the PR has an accompanying issue (closes #0000) and the maintainers have approved on my working plan.

Motivation

This PR updates BrowserOnly to support React 19's new use(browser()) API while keeping full backward compatibility with React 18.

Why this is needed:

• Prevents unnecessary re-renders: The old useEffect implementation always forces a double-render cycle on the client after initial mount.
• Improves CLS (Cumulative Layout Shift): In React 19, browser() gracefully bails out during SSR to a native <Suspense> fallback, eliminating visual flicker and layout shifts during hydration.
• Zero breaking changes: The component API (BrowserOnlyProps) remains exactly the same.
• Full backward compatibility: Automatically detects React 18 environments and falls back to the legacy useEffect behavior.

Extremely sorry if I made any mistakes

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[SapanMozammel]

Great integration with React 19.3+ browser() API and Suspense bailout handling! Clean fallback for legacy React versions as well.