txt section numbering, @typeface :middle/:lift and html scale, NewGardinerOmni, html :leading (from dev 9fa469dd74ed)

Section headings under txt are numbered inside a @document only; @typeface
gains :middle and :lift and its :scale now means the same in html and
pdf; NewGardinerOmni ships (OFL 1.1, Mark-Jan Nederhof) and @egyptian /
@chinese replace @cjk; @table :leading and :colsep reach html; kdesc
--typeface help names the flag; @document.txt is a Python class.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

fnt/newgardineromni.css

@@ -0,0 +1,7 @@
+
+@font-face {
+  font-family: 'NewGardinerOmni';
+  font-style: normal;
+  font-weight: 400;
+  src: url('newgardineromni/Regular.ttf') format('truetype');
+}