Implement CAPTCHA

[Aidajafarbigloo]

Before sending a request to the server for metadata extraction.

[Sundraiz-Shah]

1. Google reCAPTCHA – Industry-standard CAPTCHA with strong bot detection using behavioral analysis and ML. Reliable but depends on external Google services and raises some privacy concerns.
2. hCaptcha – Drop-in alternative to reCAPTCHA with similar functionality. More privacy-focused but may show challenges more frequently.
3. Cloudflare Turnstile – Modern CAPTCHA alternative that verifies users without puzzles in most cases. Good privacy approach and better UX, but still relies on a third-party service.
4. django-simple-captcha – Self-hosted Django solution generating image-based text challenges. Easy to integrate and privacy-friendly but less effective against sophisticated bots.

Summary:

• Best security: reCAPTCHA
• Best privacy-friendly external option: hCaptcha
• Best user experience: Cloudflare Turnstile
• Best self-hosted Django option: django-simple-captcha

[Aidajafarbigloo]

@Sundraiz-Shah Let's proceed with django-simple-captcha.

[Aidajafarbigloo]

Solved in #271