upstream-sync 2026-08-10: merge conflicts need manual resolution

[Theralley]

Merging upstream/main (684b3d8e05263a7c1948d3d0699ab1cb4f77c3d5, 430 new commits)
into main produced conflicts.

Resolve manually per docs/ant/upstream-sync.md §§1–2 (sentinel
rules), then push the sync branch and open the PR yourself.

[mnriem]

Closing out as spam