Valid and invalid combinations

DAIU 1.0 allows only some origin and level pairs.

Origin	None	Assist	Remix	Major	Full
HM (Human Made)	✓	✓	✓	✕	✕
AG (AI Generated)	✕	✕	✓	✓	✓

1. HM + Major and HM + Full are invalid because AI would be the primary creator at that level.
2. AG + None and AG + Assist are invalid because an AI origin implies non trivial AI involvement.

Validation tools should treat invalid pairs as errors and prompt users to choose a valid combination.