http: add IPv6 range support for NO_PROXY environment variable

[haramj]

This PR resolves the // TODO(joyeecheung): support IPv6. comment in internal/http.js by adding comprehensive support for IPv6 address ranges to the NO_PROXY environment variable.

Previously, the ProxyConfig class's shouldUseProxy method could only handle IPv4 address ranges. With this change, users can now specify IPv6 ranges (e.g., ::1-::100) to correctly bypass proxies for hosts within those ranges.

The implementation involves:

• A new helper function ipv6ToBigInt to convert 128-bit IPv6 addresses into BigInts for reliable numerical comparison.
• Updated shouldUseProxy logic to check if a host is within a given IPv6 range.

This update ensures the proxy bypass feature is robust and consistent with both IPv4 and IPv6 network standards.

New test cases have been added to test/client-proxy/test-http-proxy-request-no-proxy-ipv6.mjs to verify the new functionality.

Test

• A host within the specified IPv6 range (::1-::100) correctly bypasses the proxy.
• A host outside the specified IPv6 range correctly uses the proxy.

This ensures that the new feature works as expected and does not introduce regressions to existing functionality.

/cc @joyeecheung

[nodejs-github-bot]

Review requested:

• @nodejs/http
• @nodejs/net

[codecov]

Codecov Report

❌ Patch coverage is 89.74359% with 4 lines in your changes missing coverage. Please review.
✅ Project coverage is 88.44%. Comparing base (4612c79) to head (e8735e8).
⚠️ Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
lib/internal/http.js	89.74%	4 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #59950      +/-   ##
==========================================
+ Coverage   88.25%   88.44%   +0.18%     
==========================================
  Files         703      703              
  Lines      207412   207436      +24     
  Branches    39893    39998     +105     
==========================================
+ Hits       183052   183459     +407     
+ Misses      16313    15947     -366     
+ Partials     8047     8030      -17     

Files with missing lines	Coverage Δ
lib/internal/http.js	94.84% <89.74%> (-0.47%)	⬇️

... and 37 files with indirect coverage changes

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