Add a standardized Scroll component to the component library

[Arthurk12]

Is your feature request related to a problem? Please describe.
Different parts of the application implement scrolling independently, resulting in visually inconsistent scrollbar styles across areas (chat, lists, side panels, etc.).

Describe the solution you'd like
Create a BBBScroll (or similar) component in the component library that wraps any scrollable area and automatically applies the standardized visual style — matching the scroll used in the chat. The component should be simple to use as a wrapper and handle all scrollbar styling internally.

Affected component(s)
BBBScroll (new component)

Proposed API / Usage Example

// Wraps any area that needs a styled scrollbar
<BBBScroll maxHeight="400px">
  <MessageList />
</BBBScroll>

// Also supports axis configuration
<BBBScroll axis="y" maxHeight="300px">
  {items.map(item => <Item key={item.id} {...item} />)}
</BBBScroll>

Additional context
The reference style is the chat scroll.