Function handle_list_agents 

pub fn handle_list_agents(registry: &AgentRegistry)

Handle –list-agents command.

Lists all registered agents with their configuration details including:

• Agent name
• Command to invoke the agent
• JSON parser type
• Whether the agent can create commits (can_commit flag)

CCS aliases (ccs/…) are displayed separately for clarity. Output is sorted alphabetically by agent name within each section.