Add signal handling, environment detection, and secrets management:
- signals.zig: graceful Ctrl+C handling and signal management
- environment.zig: user environment detection for telemetry
- secrets.zig: secrets redaction for secure logging
Improves CLI reliability and security posture.
Remove colors dependency from output.zig
Add terminal.zig for TTY detection and terminal width
Update flags.zig with color flag support
Simplify colors.zig to basic ANSI codes
Update main.zig and utils.zig exports