Add sheaf schedule playground app

Author: lawrencerowland

app-index.csv

@@ -8,3 +8,4 @@
 7,functor-atlas,functorial project-management atlas,User,,"category theory, project management, functors",,
 8,functor-atlas-project-example,interactive functorial atlas graph for project categories,User,,"functors, category theory, visualization, project management",,
 9,fibration-milestone-linking,fibration-based milestone linking toy example,User,,"category theory, fibration, project management, visualization",,
+10,sheaf-schedule-playground,interactive sheaf-style scheduling playground for local-to-global WBS consistency,User,,"category theory, project management, sheaf, scheduling, visualization",,