Capture a same-session force-reload hint (loaded renderable/message counts,
known count, truncation flag) BEFORE clearing the in-memory transcript, so the
authoritative reload requests a width that preserves what was loaded instead of
collapsing a long session to the default 30-message tail window mid-read.
Same-session force reloads render with preserveScroll. Resolves conflict with
the shipped #3306 carry-forward snapshot by keeping both (complementary).
Closes#3239.
Co-authored-by: viraatdas <viraatdas@users.noreply.github.com>