data update

docs/index.md

@@ -35,6 +35,9 @@ Ship hulls, modules, and naval combat systems.
 ### [Specialists](./specialists/_index.md)
 Characters that can be slotted into buildings to modify stats.
 
+### [Skills](./skills/_index.md)
+Research discoveries that unlock new abilities, buildings, and bonuses.
+
 ### [Systems](./systems/_index.md)
 Core game mechanics including trade, maintenance, and area effects.