hCaptcha Integration for Website Login

I want to add hCaptcha protection to the login page of my website so that every sign-in attempt is first challenged and verified before the usual authentication logic runs. You will need to:

• Insert the hCaptcha widget on the existing login form, using my site key.
• Handle the server-side verification call to hCaptcha’s API in the language the site already uses (PHP).
• Return clear error messages when verification fails and allow the login flow to continue only after a valid token is confirmed.
• Provide a short note showing me where I can swap keys or tweak the challenge parameters later.

Please keep the front-end styling consistent with the current form and do all work within a git branch so I can review the changes before merging.