Does Aniimo have a social hub city?

The city has a name: Astra. It floats, it sits at the centre of things, and it is shared rather than instanced for you alone, so the other Pathfinders walking past are real people playing the game at the same time. That is the practical difference between a hub city and a menu. You are not selecting "shop" from a list, you are going somewhere and finding other players already there.

What you actually go to Astra for is the shops, the NPCs, and the egg-hatching facilities. Eggs hatch in town, which means the city is not a place you visit once during the tutorial and forget. It is a stop on the loop. You go out, you come back, you hatch and restock, you go out again.

What the shared space is for

Because other players are standing in the same city, Astra is where group play gets arranged rather than queued for. You can trade Aniimo with other players, and you can team up for online co-op to explore the open world together, run boss battles, and take on alpha encounters and other shared activities as a group. There are challenges built to be attempted with other players rather than solo.

PvP works through direct invites. You send one, the other player accepts, and you fight a duel. It is opt-in on both sides, so standing around in a public hub does not expose you to being jumped by strangers.

Not settled: Astra is the only hub city named so far, though the game describes shared public hub zones in the plural, so whether it is the single gathering point or one of several is not settled.