[BUG] Edit/Write tools complete but UI stays stuck on spinner until ESC pressed

Description

Edit and Write tools execute successfully (files are changed), but the UI remains stuck showing the spinner (e.g., "Shimmying... 45s"). Pressing ESC reveals the operation already completed.

Environment

• Claude Code version: 2.0.76
• OS: macOS (Darwin 25.3.0)
• Chip: Apple M3 Max
• RAM: 128 GB

Steps to Reproduce

1. Start Claude Code session
2. Ask Claude to edit/write a file
3. Observe spinner continues for 30-60+ seconds
4. Press ESC - file changes are already applied

Expected Behavior

UI should update immediately when the tool completes.

Actual Behavior

UI stays stuck on spinner. File is already changed but not shown until ESC is pressed.

Additional Context

• Started suddenly on Dec 26, 2025
• Was working fine before on same version
• Happens with any model (Opus, Sonnet, Haiku)
• Not related to file size or complexity
• Tried clearing caches, reinstalling - issue persists