Phase 0: scaffold React (Vite + TS) app alongside Angular

[vibhaseshadri-cognition]

Summary

Phase 0 of the Angular → React migration (PR 1 of 7). Adds a standalone Vite + React 18 + TypeScript app in react/ that coexists with the untouched Angular app. No feature code yet — placeholder App renders a single index route.

Stack set up:

• React Router v6 (BrowserRouter in main.tsx, <Routes> placeholder in App.tsx)
• Vitest + React Testing Library + jest-dom (jsdom, v8 coverage) — smoke test src/App.test.tsx
• Playwright (chromium, webServer: npm run dev) — smoke e2e e2e/app.spec.ts (replaces Protractor going forward)
• ESLint 9 flat config (typescript-eslint, react-hooks, react-refresh, eslint-config-prettier) + Prettier matching the root config (singleQuote, tabWidth: 4, printWidth: 120, trailingComma: es5)
• vite-plugin-pwa (registerType: 'autoUpdate') with manifest ported from src/manifest.json
• .github/workflows/react-ci.yml: lint / format:check / build / test on react/** changes

Angular → React file mapping

Angular	React
src/index.html	react/index.html (meta/OG/icons/skip-link/app-loader/GA snippet kept; <app-root> → <div id="root">)
src/manifest.json	VitePWA({ manifest }) in react/vite.config.ts
src/styles.scss	react/src/styles/styles.scss (app-root:empty → #root:empty)
src/app/shared/scss/_media.scss, _theme_variables.scss, _themes.scss	react/src/styles/ (verbatim; $skull-size / 8 → math.div)
src/assets/icons, src/assets/images, src/favicon.ico	react/public/...

Tests

In react/: npm run lint, npm run format:check, npm run build, npm test (1 passing), npx playwright test (1 passing) all green.

Devin-Org: engineering

Link to Devin session: https://app.devin.ai/sessions/4b8f787ce33648ab865a05a3aa4d6cad
Open in Devin Desktop: https://app.devin.ai/desktop/session/4b8f787ce33648ab865a05a3aa4d6cad?variant=devin
Requested by: @vibhaseshadri-cognition

[devin-ai-integration]

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