DN-6: Replace stale Thinkster footer attribution with Conduit copyright and repo link

[devin-ai-integration]

Summary

Resolves DN-6.

The site footer still carried the upstream RealWorld template text ("An interactive learning project from Thinkster. Code & design licensed under MIT."). frontend/components/common/Footer.tsx now renders:

© <year> <APP_NAME> · Spring Boot 2.6.3 / Java 11 monolith · GitHub

• Year is computed at render time via new Date().getFullYear().
• App name comes from APP_NAME in frontend/lib/utils/constant.ts (currently conduit, lowercase, matching the logo) rather than a hard-coded string.
• The GitHub link points at this repo and opens in a new tab (target="_blank" rel="noopener noreferrer").
• The conduit logo link and the .attribution markup/styling are unchanged; only the text inside the span differs.

Only Footer.tsx changes.

Verification

• cd frontend && npm run build succeeds; npx tsc --noEmit reports no errors. (Note: on Node 22 the existing Next 9 / webpack 4 toolchain needs NODE_OPTIONS=--openssl-legacy-provider to run at all — pre-existing, unrelated to this change.)
• Rendered against the running backend (./gradlew bootRun) + npm run dev, checked on / and /article/testing-spring-boot-applications.

Before

Home (/):

Article (/article/testing-spring-boot-applications):

After

Home (/):

Article (/article/testing-spring-boot-applications):

Link to Devin session: https://partner-workshops.devinenterprise.com/sessions/12e931f5ac6b4d44a9b1f67ab752821f
Open in Devin Desktop: https://partner-workshops.devinenterprise.com/desktop/session/12e931f5ac6b4d44a9b1f67ab752821f?variant=devin

[devin-ai-integration]

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