Function handle_dry_run 

pub fn handle_dry_run(
    logger: &Logger,
    _colors: Colors,
    config: &Config,
    developer_agent: &str,
    reviewer_agent: &str,
    repo_root: &Path,
) -> Result<()>

Handle –dry-run command.

Validates the setup without running any agents:

• Checks PROMPT.md exists and has required sections
• Validates agent configuration
• Reports detected project stack
• Shows checkpoint status if available

Arguments

• logger - Logger for status output
• _colors - Color configuration (unused but kept for API consistency)
• config - The current Ralph configuration
• developer_agent - Name of the developer agent
• reviewer_agent - Name of the reviewer agent
• repo_root - Path to the repository root

Returns

Returns Ok(()) if validation passes, or an error if PROMPT.md validation fails.