[codex] add Cloudflare SSR for playground

[jderochervlk]

Context

This is the first slice of the playground SSR work. The docs app can keep prerendering static routes while letting /try run through Cloudflare Pages Functions.

Summary

• Enables React Router SSR for @rescript-lang/docs.
• Omits /try from React Router prerender output while keeping the existing stdlib prerender paths.
• Adds a Cloudflare Pages SSR entry/function path for /try and /try.data.
• Adds wrangler.toml for local Pages dev/deploy, including nodejs_compat and the Pages project name.
• Clears out before copying build/client so stale prerendered /try artifacts do not survive rebuilds.
• Formats the v12.3 API JSON files that were failing the existing full-repo format CI job.

Validation

• node .yarn/releases/yarn-4.13.0.cjs build:res
• node .yarn/releases/yarn-4.13.0.cjs workspace @rescript-lang/docs build:vite
• node_modules/.bin/oxfmt --check apps/docs/react-router.config.mjs apps/docs/app/entry.server.js apps/docs/server/react-router-handler.js apps/docs/functions/try.js apps/docs/functions/try.data.js
• yarn ci:format
• Wrangler Pages smoke test from fresh out: /, /try, and /try.data returned 200; /try.data included bundleBaseUrl and versions loader data.

No generated .jsx files are included in this PR.

[cloudflare-workers-and-pages]

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Status	Name	Latest Commit	Updated (UTC)
❌ Deployment failed View logs	guide	fb02aa1	May 20 2026, 08:52 PM

[github-actions]

Cloudflare deployment

Deployement ID: 0baf752a-e62c-4df2-b71a-a9377f5446cc
Deployment Environment: preview

⛅️ wrangler 4.85.0
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✨ Success! Uploaded 2 files (8401 already uploaded) (1.75 sec)

✨ Uploading _redirects
✨ Uploading Functions bundle
🌎 Deploying...
✨ Deployment complete! Take a peek over at https://0baf752a.rescript-lang.pages.dev
✨ Deployment alias URL: https://vlk-enable-cloudflare-ssr.rescript-lang.pages.dev