Frogman vulnerable to stored XSS in chat console formatter (escalation vector in multi-admin deployments)

Frogman provides headless FreePBX control. Prior to version 1.6.6, Frogman's chat-console markdown formatter (`assets/js/chat.js`'s `formatMarkdown`) inserted regex capture groups as raw HTML in four template patterns: inline code, bold, markdown links, and download links. Tool responses that reflect user-controlled fields — extension names, ring-group descriptions, IVR names, queue descriptions, etc. — could carry an HTML/JavaScript payload that executes when another admin views the response through Frogman chat. The payload runs in the viewer's session, with the viewer's permissions. FreePBX's own admin GUI escapes these same fields via `freepbx_htmlspecialchars()` throughout its view templates. The chat formatter was the leaky side. Version 1.6.6 patches the issue.