kokhlo's measurement on the trimmed PR: the zero-delivery gate also catches
type_text_synthesis_budget_exceeded, whose delivered_chars is pinned to 0
because the bounded synthesis budget declined to emit at all. That target is
not dropping synthetic keystrokes, and re-routing it to set_value replaces the
driver's own chunk recommendation with a different write path and a wrong
explanation. The gate now keys on the driver's own partial-delivery verdict;
the hint also names set_value as an action rather than a delivery rung.
f26a0949a4