Hook debug log shows output and errors separately, with the exit code

Hooks are your own commands that Claude Code runs at set moments, such as before a tool runs. When a hook fails or writes to its error stream, the debug log now shows:

• a stdout: section with its normal output
• a stderr: section with its error output
• status code N at the end when it failed, giving its exit code

Failed hooks are logged at error level, others at debug level. A hook that fails without printing anything is now logged too. Before, the log showed only one kind of output, and only when there was some.