Implemented the missing browser engine functionality to make TUT actually
browse the web.
Browser Engine Changes:
- Integrate HttpClient to fetch URLs via GET requests
- Integrate HtmlRenderer to parse and render HTML content
- Implement proper error handling for failed HTTP requests
- Add relative URL resolution for links (absolute and relative paths)
- Store title, content, and links from rendered pages
Tested with https://tldp.org/HOWTO/HOWTO-INDEX/howtos.html:
✅ Successfully fetches and displays web pages
✅ Renders HTML with proper formatting (headings, lists, links)
✅ Extracts and numbers clickable links
✅ Displays page titles
The browser is now fully functional for basic text-based web browsing!