refactor(render): TextBackend owns its atlas, and staged glyphs carry a rotation basis

include/plot/plot.hpp

@@ -43,6 +43,7 @@
 #include <plot/render/shaders.hpp>
 #include <plot/render/style.hpp>
 #include <plot/render/text.hpp>
+#include <plot/render/text_atlas.hpp>
 #include <plot/render/vertex_array.hpp>
 
 #include <plot/plot/annotation.hpp>