feat: add RFC 7239 Forwarded header support for client IP parsing

[0xERR0R]

related to #1938

adds support for "Forwarded" header (RFC 7239)

[codecov]

Codecov Report

❌ Patch coverage is 93.33333% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 90.22%. Comparing base (e199445) to head (e04c7c0).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
util/http.go	93.33%	1 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1941      +/-   ##
==========================================
+ Coverage   90.20%   90.22%   +0.01%     
==========================================
  Files          90       90              
  Lines        6445     6473      +28     
==========================================
+ Hits         5814     5840      +26     
- Misses        492      493       +1     
- Partials      139      140       +1     

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[Copilot]

Pull Request Overview

This PR adds support for parsing the RFC 7239 Forwarded header to extract client IP addresses, enhancing the existing HTTPClientIP function. The implementation prioritizes the standardized Forwarded header over the legacy X-Forwarded-For header, aligning with modern HTTP proxy standards.

Key Changes

• Implements RFC 7239 Forwarded header parsing with support for IPv4, IPv6, ports, and multiple proxy hops
• Prioritizes Forwarded header over X-Forwarded-For with proper fallback behavior
• Adds comprehensive test coverage including edge cases for various header formats

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
util/http.go	Adds parseForwardedHeader and extractIPFromForValue helper functions to parse RFC 7239 headers, and updates HTTPClientIP to check Forwarded header first
util/http_test.go	Adds 16 new test cases covering IPv4/IPv6 formats, quoted values, ports, multiple entries, obfuscated identifiers, and header priority scenarios

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