Add Redirect Checker - HTTP redirect chain analysis tool

[brancogao]

Description

Added Redirect Checker to the Testing & Quality section.

What is Redirect Checker?

An open-source HTTP redirect chain analysis tool that helps developers:

• Analyze redirect chains - Follow 301/302/307/308 redirects to their final destination
• Detect redirect loops - Identify circular redirects that break pages
• Measure performance - Track response times for each hop
• Multiple User-Agents - Test with Googlebot, Bingbot, and more

Why add it?

Redirect analysis is essential for:

• SEO professionals debugging redirect chains
• DevOps engineers verifying URL migrations
• Developers testing URL shorteners and redirects

Checklist

• The tool is open-source
• The description follows the format of other entries
• Added to the appropriate section (Testing & Quality)