[2.0 / next] latest(m) returns undefined for an uninitialized async memo after its latest() input changes (A7) #4363

Found by the async app generator (packages/web/test/async-gen, branch claude/project-thread-bgafe5), minimized.

const [s, set] = createSignal(1);
const log = [];
createRoot(() => {
  const m = createMemo(() => { const v = latest(s); return new Promise(() => {}).then(() => v); });
  createRenderEffect(
    () => { try { return latest(m); } catch (e) { return "throw:" + e.constructor.name; } },
    v => log.push(String(v))
  );
});
flush(); set(0); flush();
// log: ["throw:NotReadyError", "undefined"]

Expected: ["throw:NotReadyError", "throw:NotReadyError"]. A7 (amended 2026-09-14): "latest() of an uninitialized node throws in every scope, never undefined". The visibility-oracle "uninitialized" row pins this for a memo that is never re-asked.

Actual on next (1f558e5): after the write, latest(m) returns undefined, and a JSX hole renders undefined (or nothing). With s() instead of latest(s) in the memo, it keeps throwing NotReady as expected.