[Bug] Panic on multibyte UTF-8 character boundary in string processing

Bug Description
thread '<unnamed>' (218013803) panicked at /rustc/ed61e7d7e242494fb7057f2657300d9e77bb4fcb/library/core/src/str/mod.rs:833:21:
byte index 11 is not a char boundary; it is inside '告' (bytes 9..12) of 生成報告
note: run with RUST_BACKTRACE=1 environment variable to display a backtrace
fatal runtime error: failed to initiate panic, error 5, aborting
zsh: abort claude --dangerously-skip-permissions

Environment Info

• Platform: darwin
• Terminal: Apple_Terminal
• Version: 2.1.2
• Feedback ID: 7a31f6fe-3172-4330-916a-f6c3f1a58f19

Errors

[{"error":"Error: NON-FATAL: Lock acquisition failed for /Users/longweiwang/.local/share/claude/versions/2.1.2 (expected in multi-process scenarios)\n    at HQR (/$bunfs/root/claude:2960:2165)\n    at MKA (/$bunfs/root/claude:2960:1885)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-01-09T03:28:33.484Z"}]