Feature: add Partner Addon - allow to enable Google Recapthchat on Register page

## New Partner Feature

### Google reCAPTCHA on Custom Domain Register Page

Partners can now enable **Google reCAPTCHA** on the Register Form under their custom domain — adding bot protection to the signup flow.

#### What's New
- 🔒 **New Partner Addon: Register reCAPTCHA** — enable spam and bot protection on your whitelabel registration page
- ✅ Adds the standard "I'm not a robot" reCAPTCHA checkbox to the Register Form
- 🌐 Applies to your custom domain's registration page only — no impact on the default UChat domain
- 🛠 Configurable from Whitelabel Settings → Add-ons → Register reCAPTCHA

#### How to Use
1. Go to **Whitelabel Settings** in the left sidebar
2. Navigate to **Add-ons**
3. Find **Register reCAPTCHA** and toggle it **on**
4. reCAPTCHA will now appear on the Register Form at your custom domain URL

#### Why It Matters
- Prevents automated bot signups on your whitelabel platform
- Protects workspace integrity and reduces spam accounts
- Gives partners enterprise-grade security controls over their registration flow

> 👉 Partner-only feature. Available under **Whitelabel Settings → Add-ons → Register reCAPTCHA**.