28dd60d4fc
Rustyline's \x01...\x02 markers for ANSI codes didn't work correctly, causing cursor positioning issues and breaking line editing. New approach: build_prompt() returns (prefix, prompt) tuple where: - prefix: colored text printed before readline (contains ANSI codes) - prompt: plain text passed to readline (no ANSI codes) This ensures rustyline correctly calculates line length while still showing the colored project name.