Actually, there is definite proof that if you use ctrl-u to remove the fog of war that the AI's can 'see' this as well. The proof is that the same turn that you use ctrl-u you will instantly be contacted by and greeted by all AI's (usually this is before you have universal translator). Clearly ctrl-u allows them to see you long before one of their ships stumbles on one of your ships or planets (or vice versa).
Maybe you are right that AIs can see the map as well when revealed by cheat code. Only MAYBE. I would not be so bold and say the proof is definite - it is possible to explain the contact by other means. However, I agree that the explanation that you gave is the simplest and therefore has the most force.
However, how would you explain the following? I did the test again. This time, however, I did not reveal the map right away. Instead I waited for 4 turns. On the fifth turn I revealed the map and guess what? Thalan colony ship is happily beelining towards nearest habitable planet and has made good progress already. Evidently, it started its move on turn one. The planet is too far to be within sensors and the flagship has moved to another direction. I did the test on "cakewalk" - so there should be no sensor bonus whatsoever.
I repeated the test three times and got the same result each time except once where the nearest habitable planet was too far away for Thalans to reach. In the occasion the colony ship stayed close to the home system.
How do you explain this behaviour if you think prior knowledge is ruled out?
There's no reason to presume prior knowledge of the system on the part of the AI. It seems to me that they always grab the first planet they come to in a system even if it’s a PQ5 that’s right next to a PQ26. I've also seen the AI's have to sit with their ships for a bit if I beat them to a planet. If the AI's have prior knowledge of the system they certainly aren’t using it very well.
The example you give does not necessarily rule out prior knowledge. It seems to me that AI knows the location of NEAREST habitable planet. If it happens to be PQ5, it will take it even if there is PQ26 just two moves away. Would it fit your experience or have you had instances where AI takes low quality planet that is further away? (Further away from the direction of origin of the colony ship)
The only thing that it’s clear that the AI should have prior knowledge of are the location of anomalies since you can just set your survey ship to auto survey and go straight to unseen anomalies. If you can do this then the AI should as well.
I think it is other way around: it proved difficult to "teach" AI to search effectively. So they gave AI the knowledge of nearest anomaly. To balance things the same knowledge is avaiable to player via autosurvey. The same is true for mining ships.
As regards prior knowledge of resources then this has been confirmed by stardock staff member. To be precise: the person believed that AI has prior knowledge of the location of resoruces because of very old code.
Finally, I tend to believe that AI also has knowledge of the location of colonies (without exploring) for purposes of freighter destination. However, I have to test it more with Korx as an opponent to say with more certainty.