Add output field (io.Writer) to Manager and Engineer structs with SetOutput() methods to enable testability and output redirection. Replace all 30+ fmt.Printf/Println calls with fmt.Fprintf/Fprintln using the configurable output writer, defaulting to os.Stdout. This enables: - Testing output without capturing stdout - Redirecting output in different contexts - Following cobra best practices Closes: gt-cvfg 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>