Remove TODO, everything is in notion

TODO

@@ -1,22 +0,0 @@
-Selecting one entity at a time...
-* Affects both 2d and 3d modes seemingly equally
-* We seem to not be de-selecting something...
-* Does it happen when you play the game fast/slow?
-    * Yes
-* It only seems to happen when we capture a piece.
-
-New architecture:
-* Instead of inserting a "Selected" marker, emit a "Selected" event.
-    * Contextually this acts differently based on:
-        * If no entities are selected, insert the selected marker on that entity.
-        * If an entity is already marked selected, we emit a move event and de-select all entities.
-* Q: Should we "Select Event" a BoardIndex?
-    * Pros:
-        * Display agnostic.
-        * Easy to keep in sync between displays.
-    * Cons:
-        * Possibly umm... actually I can't think of any.
-* Emit "Selected" event which includes the BoardIndex selected.
-    * If a piece exists at that index:
-        * If a piece is already selected, emit a "Move" event and de-select the selected piece.
-        * Else mark it as selected in 2d and 3d.