fix: make delete agent button more visible with red styling

[adryserage]

Summary

The delete agent button in the AgentDetail hero section was styled as a ghost button with text-ink-faint, making it nearly invisible to users.

Changes:

• Added a red border (border-red-500/30) and subtle red background (bg-red-500/10) so the button is immediately visible
• Changed text color to text-red-400 with font-medium for better contrast
• Updated button label from "Delete" to "Delete Agent" for clarity
• Preserved hover transition effects with slightly intensified red on hover

File changed: interface/src/routes/AgentDetail.tsx (2 insertions, 2 deletions)

Test plan

• Navigate to an agent's detail page and verify the delete button is clearly visible with red styling
• Hover over the button and confirm the hover effect (slightly darker red background)
• Click the button and confirm the delete flow still works as expected
• Check on both light and dark themes for adequate contrast

[jamiepine]

Sorry I hate color in my buttons. Will make this better another way.