Add one-click deploy buttons to all demo repos + 'Deploy a demo in 5 minutes' docs page

Part of the docs & demos tracking issue: shakacode/reactonrails.com#140 (P0).

Problem

Every Next.js template ships a one-click Vercel deploy button; TanStack starters deploy via Netlify guides. None of the seven React on Rails demo repos has a deploy button, and there is no "deploy a demo in 5 minutes" page. Evaluators should be able to get a running Pro app on their own infra without reading a deployment guide first.

Work

• Add one-click deploy configs + README buttons (Render blueprint and/or Railway template; optionally Fly launch.toml) to each demo repo:
  • shakacode/react-on-rails-demo-flagship
  • shakacode/react-on-rails-demo-marketplace-rsc
  • shakacode/react-on-rails-demo-hacker-news-rsc
  • shakacode/react_on_rails-demo-octochangelog-on-rails-pro
  • shakacode/react-on-rails-demo-gumroad-rsc
  • shakacode/react-on-rails-starter-tanstack
  • shakacode/react-webpack-rails-tutorial
• Add a "Deploy a demo in 5 minutes" docs page (canonical content in react_on_rails/docs/deployment/) documenting the flow, including the node renderer process on each platform
• Show a "Deploy" action next to "Live demo | Source" on the /examples page

Notes

Pro's build-free, pay-on-deploy licensing means demos deploy free to staging-like environments — worth stating on the docs page since it removes the perceived paywall.

Acceptance criteria

• Each demo repo README has at least one tested, working deploy button; /examples links deploys; the docs page exists and is linked from the quick start's next steps.

🤖 Generated with Claude Code

Code pointers

• Examples page (add Deploy action next to "Live demo | Source"): reactonrails.com repo, prototypes/docusaurus/src/pages/examples.tsx
• "Deploy a demo in 5 minutes" canonical page: new file under react_on_rails/docs/oss/deployment/, then sync + sidebar wiring in the site repo
• Licensing note for the docs page: react-on-rails-demo-flagship is OSS; the RSC demos (marketplace, hacker-news, octochangelog, gumroad) use Pro — state how build-free/pay-on-deploy terms apply to a user's own deployed copy of each

Start with prototypes/docusaurus/src/pages/examples.tsx and the deployment documentation under react_on_rails/docs/oss/deployment/. Review the seven demo repositories and choose a tested deploy-button approach for each, including the node renderer details required by the documentation. Done means every README has a working deploy button, /examples links to deploys, and the new page is synced, sidebar-linked, and included in quick-start next steps.