Tranceiver end!
Perhaps it's because of Super Easy mode on intensity 5, the AI is extremely ineffective at responding against the Imperial fleet... It summons one last exo wave, right before the Imperial fleet beats to the core world and has already cleaned up pretty much everywhere else. The exo wave has a dozen of dragons, though it's too late.
The AI had better response against my earlier Spire fleet with all those Phoenix, Poltergeist, Hunters and things. They even managed to bottle my fleet for a while mid-game, until I managed to bait them with a swarmer fleet (with MkIII engineers and 4 factories' support) and flanked those big things from three sides.
Yeah, guessing hunter fleet location is an art. And it is much easier to put up a beachhead or stations in the middle of nowhere as bait.