feat: layout-editor + docs update

[Spiral-Memory]

Brief Title

This PR introduces a new tool named 'layout-editor', which will assist EmbeddedChat users in designing and customizing EmbeddedChat layouts in real-time with drag-and-drop functionality. It will also generate a theme object that users can use when setting up EmbeddedChat.

Acceptance Criteria Fulfillment

• [x] Adds a layout editor
• [x] Updated docs
• [x] Separated docs dir

Fixes #603

Video/Screenshots

https://github.com/user-attachments/assets/3f846616-bf33-49ca-95c7-3a6e98685476