Add a dropdown to the launcher download button to choose any supported platform

[corp-0]

Problem

Currently, users click the download button on the homepage to get the launcher. The button uses client-side logic to detect the user's OS and provide the appropriate binary. However, there are cases where:

• The user's OS is not detected, causing the button to redirect them to our GitHub releases page.
• Some users may want to download a different OS version manually.

Proposed Solution

Modify the button to function as a dropdown, with the following behavior:

1. When the OS is detected properly:
   • Clicking the main button downloads the correct binary as it does now.
   • A small chevron icon is added to indicate a dropdown. Clicking the chevron opens a list of all available OS versions.
2. When the OS is not detected properly:
   • Instead of redirecting to the GitHub releases page, the button will default to dropdown mode.
   • Clicking anywhere on the button will open the list of available OS versions, ensuring users can manually select their platform.