fix: add wait after subsections to show completed animation

Manim has a bug where animations stop at ~93% completion. When videos
pause after a subsection, they show this incomplete last frame (e.g.,
circles with visible gaps).

Solution: Call self.wait() after each subsection, same as next_slide()
does. This adds frames showing the completed animation state.

The wait() creates a separate animation file that shows the final
completed state, ensuring when video playback pauses, it shows the
complete animation instead of the 93% incomplete frame.

Reference: https://lightrun.com/answers/manimcommunity-manim-t-values-issue-that-causes-the-animations-to-not-be-finished-entirely

Author: krystophny

manim_slides/slide/base.py

@@ -333,6 +333,11 @@ def construct(self):
         if relative_animation_index < 0:
             relative_animation_index = 0
 
+        # Add wait to show completed animation state (workaround for Manim bug where
+        # animations stop at ~93% completion). Same as next_slide() behavior.
+        if self.wait_time_between_slides > 0.0:
+            self.wait(self.wait_time_between_slides)  # type: ignore[attr-defined]
+
         marker = SubsectionMarker(
             animation_index=relative_animation_index,
             name=name,