Two fixes for the truncated numbered-read flow:
- read_file(with_lineno) tokens were rebased onto numbered-body chars
(each line carries an N| prefix), so get_truncated over-advanced into
raw text and silently skipped lines. Tokens now advance by raw chars
of the complete lines shown and carry a numbered flag.
- get_truncated resumes numbered tokens as numbered lines (via
read_file with_lineno), marking them readable for edit_lineno, so
read -> get_truncated -> edit_lineno works end-to-end without gaps.