Add interactive mode support for agents with --chat flag

- Remove chat from conflicts_with_all for --agent flag
- Add chat parameter to run_agent_mode()
- Run interactive loop instead of single task when --chat is passed

Usage: g3 --agent <name> --chat

crates/g3-cli/src/lib.rs

@@ -88,6 +88,7 @@ pub async fn run() -> Result<()> {
             cli.task.clone(),
             cli.chrome_headless,
             cli.safari,
+            cli.chat,
         )
         .await;
     }