* refactor(captcha): update Cap backend to 2.0.0 API format
* feat(captcha): add Cap version config for 1.x/2.x compatibility
* fix(captcha): change Cap default version to 1.x for backward compatibility
* refactor(captcha): remove Cap 1.x compatibility, keep only 2.x support
* feat(captcha): update field names to Cap 2.0 standard - Site Key and Secret Key
* fix(captcha): update Cap field names in defaults configuration
* Add Cap Captcha support
- Add CaptchaCap type constant in types.go
- Add Cap struct with InstanceURL, KeyID, and KeySecret fields
- Add CapCaptcha method in provider.go to return Cap settings
- Add default settings for Cap captcha in setting.go
- Implement Cap captcha verification logic in middleware
- Expose Cap captcha settings in site API
This adds support for Cap captcha service as an alternative
captcha option alongside existing reCAPTCHA, Turnstile and
built-in captcha options.
* update cap json tags
