Feature Request: Show message timestamps in VS Code chat UI

Problem

The VS Code Claude Code extension chat interface does not display timestamps for messages. While the underlying data files (history.jsonl and session files) do record timestamps, the UI only shows message content without any date/time indication.

Proposed Solution

Add an optional setting to show timestamps on chat messages, e.g.:

• Hover over a message to see timestamp
• Toggle in settings to show/hide timestamps inline
• Date separators between different sessions (e.g. "June 28, 2026")

Why

Useful for reviewing long conversations, finding when something was discussed, and general UX improvement.