chore(assets): update Faxbot branding images

- Replaced the full logo and mini banner images for both dark and light themes across multiple directories.
- Updated assets in `api/admin_ui/public`, `assets`, and `site/assets/images` to ensure consistent branding in the application.

These changes enhance the visual identity of the Faxbot application, aligning with the latest design standards.

Author: Faxbot Agent