Mounting a fusion reactor (largely automated - these ships have a skeleton crew) on every big ship seems ambitious enough, why would you...sure, why not, package an automated deuterium fuel refinement facility in a box on the ship too. In another ten years you'll be getting them in Christmas crackers.

where can I read about fully-automated, ship-stable, ~zero maintenance deuterium sea-water extraction systems?

YC32

Fusion fuel is so compact, there's really no need for that. To get an idea of it, deuterium is less than 0.1% of the hydrogen in water, and there's enough in your morning shower to provide all your energy needs for a year.

Nuclear aircraft carriers go thirty years without refueling, and fusion could easily do the same.