feat(validation): Add partial support for "readOnly" properties.

[arikkfir]

This change adds support for properties marked with the JSON schema's "readOnly" marker, by preventing them from being sent in JSON payloads.

[codecov]

Codecov Report

Attention: Patch coverage is 66.07143% with 19 lines in your changes missing coverage. Please review.

Project coverage is 73.03%. Comparing base (d963216) to head (b775ce4).
Report is 127 commits behind head on main.

Files with missing lines	Patch %	Lines
...idation/readOnlyAndRequired/readOnlyAndRequired.go	44.44%	9 Missing and 1 partial ⚠️
tests/data/validation/readOnly/readOnly.go	50.00%	6 Missing and 3 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #361      +/-   ##
==========================================
- Coverage   76.58%   73.03%   -3.55%     
==========================================
  Files          24       45      +21     
  Lines        1892     2893    +1001     
==========================================
+ Hits         1449     2113     +664     
- Misses        354      603     +249     
- Partials       89      177      +88     

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[arikkfir]

Seems like the coverage report complaint refers to the Go files in the tests directory, which are basically used as golden files, not real source code - perhaps they can be excluded from the calculation by adding the exclude property to the codecov action?

Something like this (in development.yaml workflow):

- name: Upload coverage to Codecov
  uses: codecov/codecov-action@v5
  with:
    exclude: tests