stack outputs for implicit stacks

[FuNK3Y]

Describe the enhancement

terragrunt stack output provides a nice and hierarchical way to display outputs for explicit stacks (with a terragrunt.stack.hcl). It would be awesome if a similar output could be provided for implicit stacks (without terragrunt.stack.hcl)

As there is no explicit name definition for the units, the relative path of its folder shall be used as the key instead.

Additional context

The current alternative terragrunt output --all does not maintain the same hierarchical view and outputs cannot be tied to their individual unit. Outputs could also potentialy even overlap if 2 units declare one with the same name.

I am not sure how this should materialize itself: could be with the introduction on a new switch on either terragrunt stack or terragrunt output

The effort should be reasonable, as most of the logic is already implemented for explicit stacks.

PoC (Proof of Concept)

$ terragrunt output --all --stack/hierarchical
./backend_app = {
  domain = "backend-app.example.com"
}
./somefolder/frontend/anotherfolder = {
  domain = "frontend-app.example.com"
}
./mysql = {
  endpoint = "terraform-20250504140737772400000001.abcdefghijkl.us-east-1.rds.amazonaws.com"
}
./somefolder/aws = {
  endpoint = "serverless-valkey-01.amazonaws.com"
}
./vpc = {
  vpc_id = "vpc-1234567890"
}

[yhakbar]

This is a really cool idea, but I have no idea whether a large number of users would use it, or if it's really that trivial to implement. I think we would need to see more interest from the community before we could consider it seriously.