Does Syncthing work over a mesh network?
In principle, yes. But you’ll have to be a bit more specific what technology you mean by mesh network so we can give a meaningful answer.
Like NYC Mesh and Locha Mesh to be specific. I am wondering how resilient Syncthing can be in a P2P world or if the internet get shutdown in your area.
Syncthing works over a network connection. Whether that’s wired internet, WiFi, Bluetooth, some mesh network, etc. shouldn’t matter. If the network doesn’t behave like a LAN (multicast/broadcasts aren’t visible to clients) and you don’t have internet connectivity, then you may need to figure out your own discovery mechanism for how devices should find each other.