Thanks @rcsr for this solution.
In manifest.yml, I think you meant
modules:
macro:
- key: forge-starter-app-hello-world-macro
resource: macro
render: native
resolver:
function: macro-resolver # instead of space-page-resolver
title: forge-starter-app
In How to split resolvers in multiple files? - #3 by BertrandDrouhard1, there is a solution to also have share files and avoid conflicts. The mix of your solution and this solution seems to solve the whole situation!