chore: cleanup (#47)

<!-- CURSOR_SUMMARY -->
> [!NOTE]
> **Medium Risk**
> Removes Terramate bundle definitions and their generated Terraform
stacks for ECS Fargate (VPC/ALB/service) and an S3 bucket, which could
lead to infrastructure being unmanaged or destroyed if applied.
> 
> **Overview**
> Removes the Terramate `BundleInstance` configs for the `catalyst-ecs`
Fargate cluster, `catalyst-nginx` service, and the
`terramate-catalyst-example-bucket` S3 bucket.
> 
> Deletes the corresponding generated Terraform stacks under
`stacks/dev` (VPC, ECS cluster, ALB, and nginx workload) and
`stacks/dev`/`stacks/stg` for the S3 bucket, including backend/provider
and stack metadata files.
> 
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
f5bb261. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

Author: soerenmartius