text: Title: [UI][XXS] Make the logo in the sidebar have rounded edges
  Body: **Description:**  
  Update the logo in the sidebar to have rounded edges for a smoother appearance. The logo is defined in the following file and line:  
  [Sidebar.jsx](https://github.com/StructuredLabs/preswald/blob/4a04b97229185e6bc22117e0c947196f60b64c6e/frontend/src/components/Sidebar.jsx#L9)
  
  **Acceptance Criteria:**
  1. The logo in the sidebar should have rounded edges.
  2. Verify the update does not introduce any UI/UX regressions.