[BUG] Claude Desktop permission dialogs render but are non-interactive on macOS 26.4

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?

Claude Desktop becomes unresponsive after launching a cowork session. The permission dialog (e.g. AskUserQuestion) renders visually but buttons are not clickable — the entire UI is non-interactive. The main process CPU stays low (~1%), so this is not the infinite-loop DST bug from #32167, but a renderer-level freeze.

Cmd+R (force refresh) has no effect. The only recovery is killall -9 Claude.

What Should Happen?

Permission dialogs should be fully interactive — buttons should respond to clicks and the UI should remain responsive throughout cowork sessions.

Error Messages/Logs

# Last meaningful log lines before freeze:
2026-03-26 15:57:53 [info] Emitted tool permission request 4f990fd0-a80e-46c0-a87e-e138d1a10154 for AskUserQuestion in session local_182303fb-f5c2-4eef-aa5e-4468cffa1f31
# After this, only heartbeats — no further UI interaction logged
2026-03-26 15:57:55 [info] [transport:ccr] Heartbeat sent
2026-03-26 15:58:15 [info] [transport:ccr] Heartbeat sent
...

Steps to Reproduce

1. Launch Claude Desktop on macOS 26.4
2. Start a cowork session (e.g. "explore files on this device and prepare a backup plan")
3. Wait for the session to emit a tool permission request (e.g. AskUserQuestion)
4. The permission dialog appears visually but buttons are not clickable
5. The entire UI becomes non-interactive

Claude Model

• Opus

Is this a regression?

I don't know

Claude Code Version

1.1.8629 (Claude Desktop), 2.1.84 (Claude Code CLI)

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Terminal.app (macOS)

Additional Information

• macOS: 26.4 (Build 25E246)
• Chip: Apple M4 Max
• RAM: 36 GB
• Install method: Homebrew cask

What was tried (none resolved):

• Force-quit and relaunch
• Full reset of ~/Library/Application Support/Claude/
• Force reinstall via brew install --cask --force claude
• Deleting local-agent-mode-sessions directory (fixes the separate DST issue from #32167 but not this one)
• Cmd+R to force-refresh the renderer

Process sample while frozen shows main thread idle in NSApplication run → CFRunLoopRunSpecificWithOptions event loop — not spinning, just not processing UI events. The renderer process (PID with --type=renderer) is also at low CPU but unresponsive to input.

Related but distinct from #32167 — that issue is a 100% CPU infinite loop caused by DST timestamps in scheduled tasks. This issue is a renderer freeze at normal CPU where the UI draws but doesn't accept input.