Nebula: Set Beta badge in sidebar (#6897)

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## PR-Codex overview
This PR updates the text displayed within the `Badge` component in the `ChatSidebar.tsx` file, changing it from "Alpha" to "Beta".

### Detailed summary
- Changed the text inside the `Badge` component from `Alpha` to `Beta`.

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Author: MananTank

apps/dashboard/src/app/nebula-app/(app)/components/ChatSidebar.tsx

@@ -46,7 +46,7 @@ export function ChatSidebar(props: {
         </Link>
 
         <Badge variant="secondary" className="gap-1 py-1">
-          Alpha
+          Beta
         </Badge>
       </div>