Visual distinction between user prompts and model responses in panel view

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

Add visual distinction between user prompts and model responses in panel view (e.g. different background color or border)

Proposed Solution

User messages should have a visually distinct background color or left border
(e.g. subtle blue/purple tint), while model responses remain with the default
background. This should follow the current VS Code theme colors if possible,
or be configurable via settings.json (e.g. "claudeCode.userMessageColor").

Alternative Solutions

Currently using no workaround – the conversation history is hard to scan
when prompts and responses look identical. A simple timestamp or "You:" /
"Claude:" label with a different color would already help significantly.

Priority

Medium - Would be very helpful

Feature Category

Other

Use Case Example

_No response_

Additional Context

_No response_