Replace monaco editor's useMonaco hook with its loader

[jeesunikim]

I kept seeing nextjs error whenever the page has Monaco Editor. Claude found that

the useMonaco() hook from @monaco-editor/react has a bug — its internal loader.init().then(...) call has no .catch(). In React StrictMode (used by Next.js), effects are double-invoked, so the cleanup calls loader.cancel() which rejects the promise with a { type: 'cancelation' } object. This surfaces as an unhandled [object Object] rejection error in Next.js.

This PR fixes nextjs error in dev setup.

[Copilot]

Pull request overview

Fixes Next.js dev unhandled promise rejection triggered by @monaco-editor/react loader cancellation under React StrictMode by replacing useMonaco() usage with a manual loader.init() flow.

Changes:

• Remove useMonaco() usage and gate rendering on a local isReady state.
• Initialize Monaco via loader.init() and attach a .catch() to prevent unhandled rejections.
• Add an optimization to skip async init when Monaco is already loaded.

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[stellar-jenkins]

Preview is available here:
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[stellar-jenkins]

Preview is available here:
http://laboratory-pr1941.previews.kube001.services.stellar-ops.com/

[stellar-jenkins]

Preview is available here:
http://laboratory-pr1941.previews.kube001.services.stellar-ops.com/

[stellar-jenkins]

Preview is available here:
http://laboratory-pr1941.previews.kube001.services.stellar-ops.com/