The line-based pager always kept at least one whole line, so a stored line
larger than the page byte ceiling was returned in full and could overflow
history (retrieval bypasses the result-bounding wrapper). Page by byte
offset instead: every page is bounded by the byte budget even inside one
oversized line, a partial UTF-8 char at the window edge is dropped and
re-read on the next page, and paging forward reconstructs the output
byte-for-byte.
Ahmed Allam
cc57e7a29b