feat(tools): support Json type for DRF JSONField and render as {Json}

[0RAJA]

• Map serializers.JSONField to FieldType.JSON
• Keep nested serializer properties as dict for stable comparisons
• Update tests to expect {Json} rendering and schema type

BREAKING CHANGE: JSONField is now exposed as Json type in schema and render output, not String.

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 82.30%. Comparing base (37d5657) to head (3e9f614).

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #91      +/-   ##
==========================================
+ Coverage   82.29%   82.30%   +0.01%     
==========================================
  Files         101      101              
  Lines        3665     3668       +3     
==========================================
+ Hits         3016     3019       +3     
  Misses        649      649              

☔ 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.