fix(web): Tab nests under tab-separated numbered parents at their content column

A tab after a list marker advances to the next four-column stop, so
`1.<tab>parent` puts content at column 4. Tab counted it as one column
and indented the child three spaces, which Markdown renders flat.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
1fc61c6059Julius Marminge committed on 10/22/2026, 7:31:29 PMparent903b0e3
2 files changedLine totals unavailable