Phase 3: integrate React features, Playwright e2e, docs; remove Angular

[vibhaseshadri-cognition]

Summary

Final migration phase. Merges the four Phase 2 feature branches (#714 #715 #716 #717) and wires them into the shell, replaces Protractor with API-mocked Playwright e2e, points hosting/CI/docs at react/, then removes the Angular source and dependencies.

Route wiring (react/src/App.tsx), mirroring Angular's lazy item/user modules:

const ItemDetails = lazy(() => import('./features/item').then((m) => ({ default: m.ItemDetails })));
const UserProfile = lazy(() => import('./features/user').then((m) => ({ default: m.UserProfile })));
<SettingsProvider><Layout><Suspense fallback={<Loader/>}>
    <AppRoutes Feed={Feed} ItemDetails={ItemDetails} User={UserProfile} />
</Suspense></Layout></SettingsProvider>

react/src/app/placeholders.tsx (Phase 2 route contract) is deleted.

Playwright e2e (react/e2e/) intercept **/node-hnapi.herokuapp.com/** via installApiMocks(page) + fixtures so runs are deterministic: feeds (all 5 types + jobs header), pagination (More only at 30 items, Prev/<ol start=31> on page 2), item (open item, collapse/expand [-]/[+], deleted comment, mobile back button), user, settings (3 themes → wrapper class + localStorage, open-in-new-tab → target=_blank, font size / list spacing CSS, close). CI workflow now runs on every push/PR (no react/** path filter) and gained an e2e job.

Hosting/CI/docs: firebase.json → public: react/dist; .travis.yml → Node 20, cd react && npm ci && npm run build; README/CONTRIBUTING rewritten for the Vite/Vitest/Playwright commands.

Angular removal (last two commits): src/, e2e/ (Protractor), angular.json, karma.conf.js, tslint.json, tsconfig*.json, browserslist, ngsw-config.json, yarn.lock; root package.json keeps only delegating scripts (npm --prefix react run …) and no dependencies.

Angular → React mapping (cumulative)

Angular	React
src/app/app.component.*, app.module.ts	react/src/App.tsx, react/src/core/Layout.tsx, useGoogleAnalytics.ts
src/app/app.routes.ts	react/src/app/routes.tsx
src/app/core/{header,footer,settings}	react/src/core/{Header,Footer,Settings}.tsx
src/app/feeds/{feed,item}	react/src/features/feed/{Feed,StoryItem}.tsx
src/app/item-details/**	react/src/features/item/{ItemDetails,Comment}.tsx
src/app/user	react/src/features/user/User.tsx (UserProfile)
src/app/shared/components/{loader,error-message}	react/src/shared/components/{Loader,ErrorMessage}.tsx
src/app/shared/services/*, pipes/comment.pipe.ts, models/*	react/src/shared/{services,utils,settings,models}
src/app/shared/scss/*, src/styles.scss	react/src/styles/*
e2e/ (Protractor)	react/e2e/*.spec.ts (Playwright)
ngsw-config.json / src/manifest.json	vite-plugin-pwa in react/vite.config.ts

Tests

react/: lint, format:check, build, Vitest 19 files / 105 tests, Playwright 11 tests — all passing locally (Node 20). Root npm run build delegates correctly.

Rendered against the live API (/news/1, then Night theme via the settings cog):

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

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