You're going to hate this, but one answer might be blockchain. A crytographically strong, attestable public record of appending information to a shared repository. Combined with cryptographic signatures for humans, it's basically a secure, open git repository for human knowledge.
Sounds interesting, but I guess I'm a little unsure of how to connect the dots? Are you suggesting that websites would be hosted on a blockchain and browsed by human-signed browsers? Or more like there would be a blockchain authority, which server hosts could query to determine if a signature, provided by their browser, is human? Would you mind painting the picture in a little more detail?
You can have cryptographically signed data caches without the need for a blockchain. What a blockchain can add is the ability to say that a particular piece of data must have existed before a given date, by including the hash of that data somewhere in the chain.
We're rarely going to need to attest anything is "real" or "human". It's basically only going to matter in civil and criminal court, and IDV.
We don't need to attest signals are analogue vs. digital. The world is going to adapt to the use of Gen AI in everything. The future of art, communications, and productivity will all be rooted in these tools.
> Combined with cryptographic signatures for humans
What happens when the human gives an agent access to said signature? Then you fall back on traditional anti-bot techniques and you're right back where you started.