When a command's output exceeds DEFAULT_MAX_BYTES the Bash tool spills the full output to a temp file. The file was opened in text mode without an explicit encoding, so it used the platform locale encoding (cp936/GBK on Chinese Windows). Output containing emoji or other characters not representable in that codepage raised UnicodeEncodeError, which propagated out and turned a successful command (exit code 0) into a tool error, discarding all output.
Open the temp file with encoding='utf-8', matching the sibling temp file written in _rewrite_long_python_c. Adds a regression test.
Co-authored-by: Cursor <cursoragent@cursor.com>
