This is a very interesting direction. The idea that dark matter could be a record of past decoherence events that then feeds back into future structure formation reminds me of a more general principle: history-dependent dynamics. In your “active archive” picture, the gravitational field is encoding where previous quantum selections occurred, and then biasing where future ones are likely to happen. That effectively introduces a kind of “inertia in configuration space,” where past realizations constrain future possibilities without fully determining them.
What I find particularly compelling is that this connects to a broader class of ideas where gravity (or dark matter) behaves like an information/entropy-related phenomenon rather than a particle sector, similar in spirit to approaches like emergent gravity.