made theme settings apply in background to speed up startup time

.tmux.conf

@@ -1230,10 +1230,11 @@ run -b '[ -z "#{window_active}" ] && [ -z "#{version}" ] && tmux set display-tim
 #   fi
 #
 #   _apply_overrides
-#   _apply_bindings
-#   _apply_theme
+#   _apply_theme&
+#   _apply_bindings&
 #   # shellcheck disable=SC2046
 #   tmux setenv -gu tmux_conf_dummy $(printenv | grep -E -o '^tmux_conf_[^=]+' | awk '{printf "; setenv -gu %s", $0}')
+#   wait
 # }
 #
 # _urlview() {