[nostalgia/core/studio,studio] Give TileSheetEditor Ctrl-A and Ctrl-G for selection

src/olympic/studio/modlib/include/studio/selectiontracker.hpp

@@ -111,6 +111,10 @@ class SelectionTracker {
 					allowStart);
 		}
 
+		constexpr void reset() noexcept {
+			m_selectionOngoing = {};
+		}
+
 		constexpr void finishSelection() noexcept {
 			m_selectionOngoing = {};
 		}