feat: support pretty printing in tojson filter (#681)

[SHYXIN]

Summary

The custom tojson filter now accepts an optional indent parameter, enabling pretty printed JSON output in templates. Default behavior is unchanged.

Changes

• starlette_admin/base.py:255 — Added indent=None parameter to the tojson filter lambda

Usage

{{ data|tojson }}           # compact (default, backward compatible)
{{ data|tojson(indent=2) }} # pretty printed with 2-space indent

Users can override the JSONField display template to use pretty printing:

JSONField("json_data", display_template="admin/json_pretty_print.html")

With a custom template:

<div class="field-json">{{ data|tojson(indent=2) }}</div>

Testing

• All 16 tests pass (test_views.py + test_converters.py)

Additional

Includes chore commit to fix pyproject.toml pytest config conflict.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (0f684fe) to head (9532f25).

Additional details and impacted files

@@            Coverage Diff            @@
##              main      #769   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           86        86           
  Lines         6848      6848           
=========================================
  Hits          6848      6848           

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