If I had to make a decision: I would do both, with a clear split. The event record because live signals like AI agent's trust score are ephemeral (among many other things). The versioned entities because you will need to answer questions nobody has thought of yet (you keep scalability intact). But the bigger win is making decisions replayable rather than merely recorded, because a receipt is a claim and a replay is a proof. Hope this makes sense!
Best, Lokesh
