Plans above 200k characters are no longer approvable from the prompt

Markdown rendering computes a marker for each list item and passes down a listIndent: second-level nesting numbers as a/b/c, and third-level nesting as roman numerals, unless the last item's number exceeds 3999, in which case it falls back to plain digits.

Continuation lines within a list item are now indented under the item's marker, except when the item begins with a code block, blockquote, horizontal rule, table, or nested list.