- appLayout.tsx: restore the 1-row placeholder when `showStickyPrompt`
is false. Dropping it saved a row but the composer height shifted by
one as the prompt appeared/disappeared, jumping the input vertically
on scroll.
- useInputHandlers: gateway.rpc (from useMainApp) already catches errors
with its own sys() message and resolves to null. The previous `.catch`
was dead code and on RPC failures the user saw both 'error: ...' (from
rpc) and 'failed to toggle yolo'. Drop the catch and gate 'failed to
toggle yolo' on a non-null response so null (= rpc already spoke)
stays silent.