[BUG] VirtualFile.refresh() called synchronously on EDT causing IntelliJ freeze

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

The Claude Code plugin calls VirtualFile.refresh() synchronously inside a write
action on the EDT (DiagnosticTools.kt:96). This causes the entire JobScheduler
fork-join pool (23 threads) to block on HighlightInfoUpdaterImpl's synchronized
monitor, freezing IntelliJ for several seconds.

Happens multiple times per day during normal usage.

threadDump-20260426-060558-1777176358293.txt

What Should Happen?

File operations complete without blocking the UI thread

Error Messages/Logs

Steps to Reproduce

1. Open any project in IntelliJ with Claude Code plugin active
2. Use Claude Code to perform any file operation
3. IntelliJ UI freezes for several seconds

Claude Model

Sonnet (default)

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.119

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Terminal.app (macOS)

Additional Information

_No response_