JSON WAF Non-JS Client Test v3

Upload/extract so the root directory is:

json-test/

Main pages:
- /json-test/
- /json-test/php-curl-test.php
- /json-test/api-test.json

Changes in v3:
- Adds "Capture cURL verbose trace" checkbox.
- Shows cURL trace in a collapsible details section.
- Keeps v2 PHP 7-compatible cache-buster fix.
- Keeps Request Sent section with method, final URL, User-Agent, headers, and equivalent curl.exe command.

Note:
The trace is PHP cURL verbose output, similar to `curl.exe -v`, not a full HAR.
