The last milestone landed on main as a squash, so main was no longer an
ancestor of next and git merge-tree reported a TODO.md conflict: both
branches added the same block of Completed Steps entries, and next added
one more (the #99 http.Server timeouts entry). This real merge commit
makes main an ancestor of next again. TODO.md is resolved by hand to keep
every entry from both sides exactly once, which is next's version since
next's entries are a superset of main's. Every other file already equals
next. No new TODO.md entry is added, per the task brief.
Model: opus-4-8
