VK OAuth / PKCE files

1. Edit config.php:
   - VK_APP_ID
   - VK_REDIRECT_URI

2. Add exactly the same VK_REDIRECT_URI in your VK ID app settings.

3. Upload all PHP files to the same directory on an HTTPS-enabled web server.

4. Open:
   https://YOUR-DOMAIN/vk/vk-auth.php

5. After authorization, vk-callback.php will display the User Access Token.

Important:
- Scope requested: friends
- Do not publish access_token or refresh_token.
- These files do not call friends.delete and do not remove anyone from friends.