feat(json/unstable): implement RFC 8785 JSON canonicalization

[tomas-zijdemans]

Implements RFC 8785 (Canonical JSON), providing deterministic JSON serialization for cryptographic hashing and signing. Used by AP2 and other security-sensitive protocols.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 94.09%. Comparing base (007896d) to head (ca58497).

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #6965   +/-   ##
=======================================
  Coverage   94.09%   94.09%           
=======================================
  Files         600      601    +1     
  Lines       43565    43614   +49     
  Branches     6999     7016   +17     
=======================================
+ Hits        40991    41038   +47     
- Misses       2519     2521    +2     
  Partials       55       55           

☔ View full report in Codecov by Sentry.
📢 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.