Use TMUX_LAYOUT_FULLSCREEN instead of heuristic

Only change `window-wide-left`/`window-wide-right` to 63%/37% split when
`TMUX_LAYOUT_FULLSCREEN=1`.

layouts/window-wide-left

@@ -2,7 +2,7 @@
 
 cols=`tmux display -p "#{pane_width}"`
 
-if [[ $cols -gt 300 ]]; then
+if [ "$LAYOUT_FULLSCREEN" = "1" ]; then
   tmux split-window -h -l 37% -c '#{pane_current_path}'
   tmux select-pane -t 1
 else

layouts/window-wide-right

@@ -2,7 +2,7 @@
 
 cols=`tmux display -p "#{pane_width}"`
 
-if [[ $cols -gt 300 ]]; then
+if [ "$TMUX_LAYOUT_FULLSCREEN" = "1" ]; then
   tmux split-window -h -l 63% -c '#{pane_current_path}'
   tmux select-pane -t 1
 else

tmux.conf

@@ -58,6 +58,10 @@ if '[ ! -n $ITERM_PROFILE ]' \
 # Enable strikethrough on VTE compatible terminals.
 set -ga terminal-overrides 'xterm*:smxx=\E[9m'
 
+# Binding to create window-auto layout
+bind a run-shell ~/.local/share/tmux/layouts/window-auto
+# TODO: bind A run-shell ~/.local/share/tmux/layouts/window-auto --refresh
+
 # Set only on macOS where it's required
 if -b '[ "`uname`" = "Darwin" ]' \
   'set -g default-command "reattach-to-user-namespace -l $SHELL"'