Nexus Data Download: add proper behaviour if file is too big to download on the browser

In some cases, files can be really large (40+ GB). The browser has a limitation of the file size, and right now, Nexus does not zip + split the file into smaller chunks.

1. Investigate the size limit
2. Can we find a workaround?
3. If not, disable the Download and display a message saying "This file is too big to download directly in the browser. Please use ____." when the file is over the size limit.

Acceptance Criteria:

- Show proper error message for large files (based on browser limit)
- "This file is too large to download in the browser. You can use the following command in your terminal:"
- Disable download (greyed out) button.
- Provide the curl command for Delta, including the token.
- Users can copy the command and paste it into their terminal.

No files, tests, or entry points are named in the issue. Start by locating the browser download flow and determining the applicable browser size limit, then assess whether chunking is feasible; done means oversized downloads are disabled with the specified message and a copyable Delta curl command including the token.

Written by the indexing model from the issue text.