Widget: Redesigned chat UI and npm package

The embeddable widget got a complete visual overhaul and is now installable via npm as supportwire-widget.

What's new

• A redesigned message layout with glassmorphism bubbles, a gradient glow trigger, and fullscreen image previews.
• Rich text editing in the message input.
• Unread message count tracking with badge updates and notification sounds.
• Published as supportwire-widget on npm with domain, user token, and app URL configuration.
• Programmatic message sending via the widget API for custom integrations.