While a reply streams, presentation reparses only the growing last Markdown
block: the cached block text plus the new chunk. splitMarkdownBlocks drops a
trailing whitespace-only line, and only trailing "\n"s were added back, so a
reply that paused on "]\n " cached the block as "]". The next chunk " B -->"
then continued the previous line, joining two lines of a code block. Codex
streams a line break and the next line's indent as separate deltas, so its
Mermaid diagrams hit this and failed to render. History reparses the whole
text, which is why a reload showed the reply correctly.
Keep every trailing blank line the split drops on the last block.
Closes#5456
Co-authored-by: paseo-bot[bot] <266920839+paseo-bot[bot]@users.noreply.github.com>
paseo-bot[bot]
f4ba16a0b3