quic: refresh session path addresses

[manNomi]

Description

QuicSession#path currently caches the SocketAddress instances created on first access. When a client follows a server's preferred address, ngtcp2 updates the connection path but later session.path reads continue to expose the original addresses.

Read the current path from ngtcp2_conn_get_path2() and refresh private address state whenever session.path is accessed. The public path object remains cached and its local and remote properties are read-only, so freezing the returned object does not prevent later internal refreshes.

Extend the preferred-address migration test to verify the initial and migrated paths, preserve the cached object identity, and cover a frozen path object. Document the cache and refresh behavior.

[nodejs-github-bot]

Review requested:

• @nodejs/quic

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 90.05%. Comparing base (2247054) to head (6e30e5f).
⚠️ Report is 3 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #65733      +/-   ##
==========================================
- Coverage   90.05%   90.05%   -0.01%     
==========================================
  Files         755      755              
  Lines      257100   257128      +28     
  Branches    48730    48737       +7     
==========================================
+ Hits       231544   231567      +23     
+ Misses      16675    16650      -25     
- Partials     8881     8911      +30     

Files with missing lines	Coverage Δ
lib/internal/quic/quic.js	100.00% <100.00%> (ø)

... and 41 files with indirect coverage changes

🚀 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.