[BUG] `stop_reason` is always `None`

Environment

• Platform (select one):
• [x] Anthropic API
• [ ] AWS Bedrock
• [ ] Google Vertex AI
• [ ] Other: <!-- specify -->
• Claude CLI version: <!-- output of claude --version -->1.0.10 (Claude Code)
• Operating System: <!-- e.g. macOS 14.3, Windows 11, Ubuntu 22.04 -->N/A
• Terminal: <!-- e.g. iTerm2, Terminal App -->N/A

Steps to Reproduce

1. update to v1.0.10
2. run claude -p "run ls" --output-format stream-json --verbose
3. look at the ouput

Expected Behavior

<!-- What you expected to happen -->
tool_use/end_turn/etc values for stop_reason