[4/7] React migration: Feed and Item components with the five feed routes

[devanshi-gpta]

Summary

Ports src/app/feeds/ and wires up routing: / redirects to /news/1, and news|newest|show|ask|jobs share one Feed component parameterised by feed type, matching app.routes.ts.

• Feed replaces the RxJS subscription with a useEffect fetch keyed on feed type and useParams().page, aborting the in-flight request on change so a fast page switch can't render stale stories.
• Item keeps the Angular template's link semantics exactly, including [attr.target]="openLinkInNewTab ? '_blank' : null" → target={settings.openLinkInNewTab ? '_blank' : undefined}, and the job-type branch that omits points and comments.
• Feed.scss's bare a { font-weight: bold } is narrowed to .job-header a, .nav a. Under Angular it applied only inside the feed template; imported globally it would have bolded every story title rendered by Item.
• Vitest/RTL tests cover pagination link state, the error path, and item link behavior.

Proposed fixes

• Add Feed.tsx / Item.tsx with stylesheets and tests.
• Add the redirect and five feed routes to App.

Link to Devin session: https://app.devin.ai/sessions/a3a0ff57bab64e25860349a003a282ef
Open in Devin Desktop: https://app.devin.ai/desktop/session/a3a0ff57bab64e25860349a003a282ef?variant=devin
Requested by: @devanshi-gpta

[devin-ai-integration]

🤖 Devin AI Engineer

I'll be helping with this pull request! Here's what you should know:

✅ I will automatically:

• Address comments on this PR. Add '(aside)' to your comment to have me ignore it.
• Look at CI failures and help fix them

Note: I can only respond to comments from users who have write access to this repository.

⚙️ Control Options:

• Disable automatic comment, CI, and merge conflict monitoring