Extract shared plot label positioning into _position_plot_labels()

Set layout engine in _create_figure() instead of draw()

Rename _equalize to _align and simplify call sites

Convert iter_*_spaces methods to properties on LayoutTree

Use helper functions to adjust the plot footer

Use one TextJustifier class

Use a common helper function to align spaces

A helpful comment about gridspec nesting

Clean up p9GridSpec: fix axes ownership, inline update, remove dead code

Warn when aesthetics are dropped during stat processing

Exclude geom from forwarded stat kwargs when resolving pre-built instances

Add aes.__repr__

Move stat, position and na_rm out of individual DEFAULT_PARAMS into base class defaults

Use safe dict access for geom/stat params and remove geom default from stat.DEFAULT_PARAMS

Merge kwargs into geom/stat instance params when resolving pre-built instances