Panic when truncating UTF-8 Chinese characters in status display

Bug Description

Claude Code CLI panics when displaying status text containing Chinese characters. The string truncation logic does not properly handle UTF-8 character boundaries.

Error Message

thread '<unnamed>' (24839166) panicked at /rustc/ed61e7d7e242494fb7057f2657300d9e77bb4fcb/library/core/src/str/mod.rs:833:21:
byte index 11 is not a char boundary; it is inside '援' (bytes 9..12) of `工具支援 `
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

Root Cause

The string 工具支援 (meaning "tool support" in Chinese) is being truncated at byte index 11, which falls in the middle of the character 援 (bytes 9-12). In UTF-8 encoding, Chinese characters occupy 3 bytes each. The truncation logic is cutting at a byte offset that is not a valid UTF-8 character boundary.

Expected Behavior

String truncation should respect UTF-8 character boundaries and only cut at valid positions.

Environment

• OS: macOS (Darwin 24.6.0)
• Shell: zsh

Suggested Fix

When truncating strings for display, use character-aware methods like str.char_indices() to find valid truncation points, or use a crate like unicode-segmentation for proper grapheme cluster handling.