Opening a session (or any relayout that shrinks off-screen size estimates)
could leave the viewport in a phantom tail below the measured content, with
every row out of reach above; a totalSize-change check now detects the
fully blank viewport and returns to the real end, and settling a width
resize re-asserts the end for a reader who was on it. Prompt-rail and
message jumps land on estimated offsets that shift as the target mounts and
measures; a short settle loop now re-aligns the target until layout rests,
backing off on the first user gesture.
Bohdan Triapitsyn
087c148b2e