fix(ui): harden summary and settings workflows

src/ui/components/ExpectedBand.tsx

@@ -174,7 +174,7 @@ export function expectedGroups(
  */
 export function ExpectedBand({ monthId }: { monthId: MonthId }) {
   const dataset = useDataset();
-  const { mutate } = useMutate();
+  const { mutate, error } = useMutate();
   const [amounts, setAmounts] = useState<Record<string, string>>({});
 
   const { pending, overdue, comingUp } = useMemo(
@@ -239,7 +239,7 @@ export function ExpectedBand({ monthId }: { monthId: MonthId }) {
             size="sm"
             variant="outline"
             disabled={invalid}
-            onClick={() => {
+            onClick={async () => {
               // Captured before mutate, per AGENTS.md: mutate defers behind
               // the write queue and React resets the input first, so reading
               // in the callback commits stale text. `invalid` already guards
@@ -247,12 +247,13 @@ export function ExpectedBand({ monthId }: { monthId: MonthId }) {
               // `parsed` is either a real amount or the field was never
               // touched.
               if (invalid) return;
-              mutate((draft) =>
+              const saved = await mutate((draft) =>
                 confirmOccurrence(draft, occurrence.recurringId, occurrence.date, {
                   date: recordedDate ?? undefined,
                   amount: parsed ?? undefined,
                 }),
               );
+              if (!saved) return;
               setAmounts((current) => {
                 const next = { ...current };
                 delete next[key];
@@ -272,6 +273,7 @@ export function ExpectedBand({ monthId }: { monthId: MonthId }) {
       title="Expected"
       hint="Committed but not yet spent. These do not touch a post's balance until you confirm one, which records it as an ordinary purchase you can edit or delete afterwards."
     >
+      {error && <p role="alert" className="mb-3 text-sm text-destructive">Could not confirm: {error}</p>}
       {pending.length > 0 && (
         <ul className="divide-y divide-budget-rule">
           {pending.map((occurrence) => row(occurrence, recordedDateFor("pending", today)))}