Brick extraction: OBJ importer #303

Current State

The OBJ importer was split from the core by #47. It is not established whether it already has its own repository, release cadence and CI boundary check.

Tasks

• Confirm the remaining coupling to core types
• Move it to its own repository and publish it as a package if it is not there yet
• Consume the package from Turian and enforce the boundary in CI

Acceptance Criteria

• The OBJ importer is released independently and Turian consumes the published package.

Related

#47, brick extraction epic