Korean text causes crash (UTF-8 byte boundary error)

Problem

Claude Code crashes 5-10 times daily when using Korean text.

Error

thread '<unnamed>' panicked at library/core/src/str/mod.rs:833:21:
byte index 15 is not a char boundary; it is inside '다' (bytes 13..16) of ` 제공합니다."`

panic(main thread): Segmentation fault at address 0x0
oh no: Bun has crashed. This indicates a bug in Bun, not your code.

Environment

• macOS 26.2 (Darwin 25.2.0)
• Bun 1.3.5
• Intel x64 (sse42 popcnt avx avx2)

Expected Behavior

Should handle Korean (UTF-8 multibyte characters) without crashing.

Additional Context

This appears to be a Rust string slicing issue where byte index is used instead of character boundary. Korean characters are 3 bytes in UTF-8, and the crash occurs when slicing in the middle of a character.