Add React 18 + Vite port of the Angular RealWorld app (migration demo)

[devin-ai-integration]

Summary

Adds a complete React 18 + Vite + TypeScript port of the Angular Conduit app under react/, for an Angular → React migration demo. The Angular app is untouched; both apps share the realworld submodule's theme CSS/media assets and hit the same API (https://api.realworld.show/api).

Migration mapping:

• UserService (RxJS) → UserContext React context with authState (loading/authenticated/unauthenticated)
• api/token/error HTTP interceptors → single fetch wrapper in react/src/api/client.ts (ApiError carries RealWorld errors shape)
• Router guards (requireAuth, guest-only) → RequireAuth / RequireGuest route wrappers
• markdown pipe (marked + DomSanitizer) → marked + dompurify in the Article page
• All pages ported: Home (global/your feed, tags), Auth, Settings, Profile (+favorites), Editor, Article (comments, favorite/follow/delete)

Also exposes the same window.__conduit_debug__ interface the Playwright e2e suite relies on.

Run: cd react && bun install && bun run start (port 4300). bun run build passes (tsc strict + vite).

Verified locally against the live API — home feed, tags, and article navigation render correctly:

Link to Devin session: https://app.devin.ai/sessions/b9422a8ea48949f49bcac46354698f57
Requested by: @patrickbradley-cog

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[devin-ai-integration]

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[devin-ai-integration]

End-to-end test results — React port

Ran the React app locally (cd react && bun run start, port 4300) against the live RealWorld API and exercised the full golden path in the browser with a fresh account. 9/9 assertions passed.

Test results

• ✅ Register a new user and authenticate
• ✅ Create article via editor (markdown rendering + tag)
• ✅ Add and delete a comment
• ✅ Edit article (editor pre-filled, slug updated)
• ✅ Favorite article; appears on profile "Favorited Articles" tab
• ✅ Update settings bio; reflected on profile
• ✅ Delete article; removed from Global Feed
• ✅ Logout restores guest nav
• ✅ Re-login with same credentials

Notes

• The live API's PUT /user 422 flake (cause of the preexisting settings.spec.ts CI failures) did not occur in this run — the bio update succeeded.
• Comment delete required a second click on the trash icon (first click missed the hit area); deletion itself works correctly.

Evidence

🟢 Article with rendered markdown + tag	🟢 Bio reflected on profile

🟢 Favorited Articles tab	🟢 Guest nav after logout

Tested by Devin