Return a non-zero exit code when no subcommands are supplied (#296)

## Type of change

- [x] Bug fix
- [ ] New feature development
- [ ] Tech debt (refactoring, code cleanup, dependency upgrades, etc)
- [ ] Build/deploy pipeline (DevOps)
- [ ] Other

## Objective

Return a non-zero exit code when no subcommands are supplied. This
matches the behavior in many other CLIs (`bw`, `git`, `ssh`, etc.).

## Code changes

<!--Explain the changes you've made to each file or major component.
This should help the reviewer understand your changes-->
<!--Also refer to any related changes or PRs in other repositories-->

- **`crates/bws/src/main.rs`:** Exit with a non-zero exit code

## Before you submit

- Please add **unit tests** where it makes sense to do so (encouraged
but not required)

crates/bws/src/main.rs

@@ -247,7 +247,7 @@ async fn process_commands() -> Result<()> {
     let Some(command) = cli.command else {
         let mut cmd = Cli::command();
         eprintln!("{}", cmd.render_help().ansi());
-        return Ok(());
+        std::process::exit(1);
     };
 
     // These commands don't require authentication, so we process them first