"Thoughts for Ns" timer increases each time the section is toggled open/closed

Description

The "Thoughts for {n}s" collapsible section displayed during conversations shows an increasing time value every time the section is expanded and collapsed.

Steps to Reproduce

1. During a conversation, wait for the "Thoughts for Ns" section to appear
2. Click the section to expand it
3. Click again to collapse it
4. Click to expand again — the displayed time (N) has increased from the original value
5. Each open/close cycle further increases the displayed time

Expected Behavior

The time value should remain stable and reflect the actual thinking duration, regardless of how many times the section is toggled.

Actual Behavior

The time value increases with each toggle, suggesting the timer continues counting (or restarts and accumulates) on each expand/collapse cycle rather than showing the fixed recorded duration.

Environment

• Claude Code (VS Code extension)
• macOS