Security: Add CSRF protection to authentication forms

[coderabbitai]

Description

The registration and login forms in the application currently lack CSRF (Cross-Site Request Forgery) protection, making them vulnerable to CSRF attacks where malicious websites could submit forms on behalf of authenticated users.

Affected Files

• templates/auth_pages/register.templ
• templates/auth_pages/login.templ
• Authentication handlers in internal/delivery/http/handler/auth_handler.go

Security Risk

Without CSRF protection, attackers can:

1. Create malicious websites that automatically submit registration/login forms
2. Potentially compromise user accounts through social engineering
3. Perform unauthorized actions on behalf of users

Proposed Solution

1. Add CSRF middleware to the application (e.g., gin-contrib/csrf)
2. Include CSRF tokens in authentication forms
3. Validate CSRF tokens on form submission

References

• Pull Request: Feat/frontend #39
• Comment: Feat/frontend #39 (comment)

Priority

High - This is a security vulnerability that should be addressed promptly.

cc @itsLeonB