Display correct web application name on the CAPTCHA verification page

Dynamically renders the web application name on the CAPTCHA page, replacing the hardcoded "Webmail" fallback and adding "Unknown App" fallback.

Replit-Commit-Author: Agent
Replit-Commit-Session-Id: 5f867144-0415-48d3-8026-4f5a0ceb78be
Replit-Commit-Screenshot-Url: https://storage.googleapis.com/screenshot-production-us-central1/a0a53cd9-b7d1-41b1-b30b-b8f47d794dda/85b55dc6-0493-469a-b66b-abd7e878a836.jpg
