Prevent command result cards from collapsing when results accumulate

Summary

After executing commands such as /model several times, previously rendered command result cards shrink until only their borders remain visible as horizontal lines.

The cards are allowed to shrink inside the message list's flex layout instead of preserving their content height.

Affected areas

• Command result cards
• Chat message list
• Conversation scrolling
• Repeated slash-command execution

Current behavior

Command result cards participate in flex shrinking while also using hidden overflow.

As more results are added, the browser compresses the cards to fit the available message-list height, eventually hiding their content.

Expected behavior

Every command result card should preserve the height required by its content.

When the results exceed the available conversation height, the message list should scroll rather than shrinking or clipping individual cards.