✨ feat(cli): implement list subcommand

- add `list` subcommand using clap
- integrate google_gmail1 crate for Gmail API interaction
- add credential loading and authentication flow

src/main.rs

@@ -1,5 +1,11 @@
 use clap::{Parser, Subcommand};
 
+mod list_cli;
+
+use cull_gmail::Credential;
+use google_gmail1::{Gmail, yup_oauth2::ApplicationSecret};
+use list_cli::ListCli;
+
 #[derive(Parser, Debug)]
 #[clap(author, version, about, long_about = None)]
 struct Cli {
@@ -13,16 +19,17 @@ struct Cli {
 enum Commands {
     /// List messages
     #[clap(name = "list")]
-    List,
+    List(ListCli),
 }
 
-fn main() {
+#[tokio::main]
+async fn main() {
     let args = Cli::parse();
 
     let mut logging = get_logging(args.logging.log_level_filter());
     logging.init();
 
-    run(args);
+    run(args).await;
     // match run(args) {
     //     Ok(_) => {}
     //     Err(e) => {
@@ -38,10 +45,17 @@ fn main() {
     // }
 }
 
-fn run(args: Cli) {
+async fn run(args: Cli) {
+    let secret: ApplicationSecret = Credential::load_json_file("credential.json").into();
+
+    let auth = cull_gmail::get_auth(secret).await;
+    let client = cull_gmail::get_client();
+
+    let hub = Gmail::new(client, auth);
+
     if let Some(cmds) = args.command {
         match cmds {
-            Commands::List => todo!(),
+            Commands::List(list_cli) => list_cli.run(hub).await,
         }
     }
     // Ok(())