`settle` and `accessibility` now also wait for loads, pages opening,
work started with spawn (template art, version copies, renames) and the
search index jobs sent but not answered, seen quiet on two frames
apart so whatever a finishing thread sent has been handled. Search
counts pending jobs in place of its busy flag, which was false until
the index thread picked a job up. Every replay test now settles in
place of its fixed waits, except after a resize, which the window
system does.

Assisted-by: claude-opus-5.5