✨ feat(cli): add message trait for cli subcommands

- introduce a trait to handle message-related operations
- implement the trait for config, delete, label, message, run, and trash subcommands

src/cli/main.rs

@@ -4,10 +4,12 @@ mod config_cli;
 mod delete_cli;
 mod label_cli;
 mod message_cli;
+mod message_trait;
 mod run_cli;
 mod trash_cli;
 
 use cull_gmail::{Config, GmailClient, Result};
+use std::error::Error as stdError;
 
 use config_cli::ConfigCli;
 use delete_cli::DeleteCli;
@@ -16,8 +18,6 @@ use message_cli::MessageCli;
 use run_cli::RunCli;
 use trash_cli::TrashCli;
 
-use std::error::Error as stdError;
-
 #[derive(Parser, Debug)]
 #[clap(author, version, about, long_about = None)]
 struct Cli {