♻️ refactor(cli): rename command to sub_command for clarity

- rename `command` field to `sub_command` in `Cli` and `ConfigCli` structs
- rename `Commands` enum to `SubCmds` to reflect its role as subcommand
- update references to the renamed fields and enum variants
- this improves code readability and avoids confusion with other command concepts

🐛 fix(config): correct method name for setting eol action

- rename `set_command` to `set_action` in `EolRule` struct
- update references in `config.rs` to use the correct method name
- this fixes a bug where the eol action was not being set correctly

src/eol_action.rs

@@ -1,6 +1,6 @@
 use std::fmt;
 
-/// End of life command
+/// End of life action
 /// - Trash - move the message to the trash to be automatically deleted by Google
 /// - Delete - delete the message immediately without allowing rescue from trash
 #[derive(Debug, Default)]