Add LinkML metamodel conformance checking to CI

[StroemPhi]

Affected: CI pipelines of both dcat-ap-plus and chem-dcat-ap
Severity: Tooling gap
Status: Not started

Problem: #101 was not caught by existing CI, which only validates instance data against the schema and the schema against LinkML syntax. A metamodel conformance check (e.g. linkml-lint? or equivalent) that validates the schema against LinkML's own structural rules would catch such violations at build time.

Action: Add a linting step to CI that checks for:

• Mixin classes used as is_a targets
• Required metamodel fields
• Inconsistent class_uri / slot_uri declarations
• Other structural violations

[dalito]

Do you have a specific command in mind that would have caught the problem? ...or was running linkml-lint enough?

[StroemPhi]

This I hoped would be something you could answer. I haven't used linkml-lint much yet. So far I only relied on just test and just gen-project to throw erorrs that show me I messed up somehow.