[Bug]: Set min-width on top-level HTML element

[rbren]

Is there an existing issue for the same bug?

• I have checked the troubleshooting document at https://docs.all-hands.dev/modules/usage/troubleshooting
• I have checked the existing issues.

Describe the bug

With the new UI, if you're in a small window, everything gets squished

We should make it so it just overflow-scrolls to the right, by setting min-width on a top-level element to sth like 1000px

Current OpenHands version

`main` branch, after @amanape's change

Installation and Configuration

dev workflow

Model and Agent

No response

Operating System

No response

Reproduction Steps

No response

Logs, Errors, Screenshots, and Additional Context

No response