Follow-up: Align site-owned create-app and examples copy with Pro-first docs

Summary

React on Rails PR #4217 changes the new-app story: npx create-react-on-rails-app my-app should now be presented as the Pro/RSC default path for React 19.2 support, with --standard as the explicit OSS-only escape hatch. The docs pages under /docs/... are sourced from shakacode/react_on_rails and should update through the existing docs-updated dispatch after that PR merges.

This issue tracks the site-owned Docusaurus pages that are not generated from the monorepo docs.

Suggested work

• Update prototypes/docusaurus/src/constants/prompts.ts so the homepage Start a new app prompt says the default generated app is the Pro/RSC React 19.2 path, and mentions --standard only as the OSS-only escape hatch if the prompt needs that caveat.
• Review /examples copy in prototypes/docusaurus/src/pages/examples.tsx and demo metadata in prototypes/docusaurus/src/constants/demos.ts for consistency with the Pro-first examples direction.
• Coordinate with #129 before adding or describing the Flagship demo: do not position it as the OSS baseline unless that is still intentionally true. The React on Rails docs now treat Flagship as a product-style baseline / possible Pro-transition reference that should be checked against its README before public stack claims.
• After PR #4217 lands and docs sync, verify the live /docs/getting-started/create-react-on-rails-app, /docs/getting-started/quick-start, and /examples pages tell one coherent new-user story.

Source

• React on Rails PR: https://github.com/shakacode/react_on_rails/pull/4217
• Related site issue: https://github.com/shakacode/reactonrails.com/issues/129

Non-goal

Do not edit generated docs directly under content/upstream/docs or prototypes/docusaurus/docs; those come from the React on Rails monorepo sync.

Start with prototypes/docusaurus/src/constants/prompts.ts, prototypes/docusaurus/src/pages/examples.tsx, and prototypes/docusaurus/src/constants/demos.ts, then review related issue #129 and PR #4217 for the intended Pro-first wording. After the upstream PR and docs sync, verify the create-app, quick-start, and examples pages present one consistent story without editing generated docs.