Security: Prevent DNS rebinding in link checker - refs GHSA-ggx3-h674-xqq3

[christianbeeznest]

Fixes GHSA-ggx3-h674-xqq3 for master.

• Prevent DNS rebinding SSRF by pinning cURL connections to validated public IP addresses.
• Preserve HTTPS hostname and certificate verification.
• Disable proxy-based DNS resolution and automatic redirects.
• Add regression tests for URL validation and connection security.

Validation:

• PHP syntax checks passed.
• PHPUnit: 4 tests passed, 20 assertions.
• Chamilo 3.1 platform testing completed.
• Live DNS-rebinding testing remains pending.

Refs GHSA-ggx3-h674-xqq3

[codecov]

Codecov Report

❌ Patch coverage is 71.15385% with 15 lines in your changes missing coverage. Please review.
✅ Project coverage is 15.63%. Comparing base (15d81f4) to head (d9cbcb2).
⚠️ Report is 2 commits behind head on master.

Files with missing lines	Patch %	Lines
src/CoreBundle/Controller/Api/CheckCLinkAction.php	71.15%	15 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #9271      +/-   ##
============================================
+ Coverage     15.60%   15.63%   +0.03%     
- Complexity    62024    62040      +16     
============================================
  Files          2515     2515              
  Lines        232866   232896      +30     
============================================
+ Hits          36335    36411      +76     
+ Misses       196531   196485      -46     

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.