A jump clicked while the Load-earlier pull was in flight fell through the
settle effect's nearest-turn fallback and landed on the wrong row. The
effect now keeps the pending jump (busy pulse stays) while loadingOlder is
true and a retry tick re-issues loadThrough when the pull settles.
Also repins the long-interactions e2e rail block to the outline-rail
semantics (fixed mark pitch, load-and-jump labels) and covers the
loadThrough forwarding paths in apply-inject and the client-runtime stub.
Tianyi Cui