Turn end with actions per turn

Normally turns end automatically when there are no actions per turn left, however I want turns to only end when the player selects a turn end action. (There are zero cost actions that players can still perform at the end of their turn, even if they have no actions per turn left).

To get around this, I'm setting a fractional actions available per turn for the player (eg 3.1). That way, when actions are used, there's always the 0.1 fraction left, preventing the automatic turn end. It's kinda awkward though - for example always having to make sure the UI doesn't show that extra 0.1 action available. Is there a more elegant way of preventing the turn ending except when the player specifically chooses to?