Fix dashboard data findings from browser verification

- Próximas cuotas: headline is the upcoming billing batch (sum of every
  active plan's next cuota, using the rounding-absorbing last cuota
  when it's the pending one) — the in-cycle formula was ~always zero
  since cuotas bill on the 19th, day one of the next cycle.
- useAgent must name the 'wealthysmart' agent (default crashed the page).
- /transactions/recent excludes future-dated Tasa Cero cuotas.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

frontend/src/pages/Asistente.tsx

@@ -27,7 +27,7 @@ export default function Asistente() {
   // append it as a user message and run the agent once.
   const location = useLocation();
   const navigate = useNavigate();
-  const { agent } = useAgent();
+  const { agent } = useAgent({ agentId: "wealthysmart" });
   const { copilotkit } = useCopilotKit();
   const sentRef = useRef(false);
   useEffect(() => {

frontend/src/pages/Inicio.tsx

@@ -132,18 +132,21 @@ function ProximasCuotasCard() {
   const active = (q.data?.plans ?? []).filter(
     (p) => !p.is_completed && p.next_cuota_date,
   );
-  const inCycle = active.filter((p) => {
-    const d = new Date(p.next_cuota_date!);
-    return d >= CYCLE.start && d < CYCLE.end;
-  });
-  const cycleTotal = inCycle.reduce((s, p) => s + p.installment_amount, 0);
-  const upcoming = [...active]
-    .sort(
-      (a, b) =>
-        new Date(a.next_cuota_date!).getTime() -
-        new Date(b.next_cuota_date!).getTime(),
-    )
-    .slice(0, 3);
+  // One cuota per plan per cycle, so the sum of every active plan's next
+  // cuota is the load of the upcoming billing batch (next 19th). The last
+  // cuota absorbs BAC's rounding, so use it when it's the one pending.
+  const nextCuotaOf = (p: (typeof active)[number]) =>
+    p.cuotas_billed === p.num_installments - 1
+      ? p.last_installment_amount
+      : p.installment_amount;
+  const nextBatchTotal = active.reduce((s, p) => s + nextCuotaOf(p), 0);
+  const upcoming = [...active].sort(
+    (a, b) =>
+      new Date(a.next_cuota_date!).getTime() -
+      new Date(b.next_cuota_date!).getTime(),
+  );
+  const nextDate = upcoming[0]?.next_cuota_date;
+  const topThree = upcoming.slice(0, 3);
 
   return (
     <StatCardShell to="/financiamientos" ariaLabel="Ver financiamientos">
@@ -151,21 +154,25 @@ function ProximasCuotasCard() {
         <CardTitle className="text-sm font-medium text-muted-foreground">
           Próximas cuotas
         </CardTitle>
-        <CardDescription>Tasa Cero en este ciclo</CardDescription>
+        <CardDescription>
+          {nextDate
+            ? `Tasa Cero · próximo cobro ${formatShortDate(nextDate)}`
+            : "Tasa Cero"}
+        </CardDescription>
       </CardHeader>
       <CardContent className="space-y-2">
         <StatValue
           loading={q.isPending}
-          value={q.isError ? null : formatAmount(cycleTotal, "CRC")}
+          value={q.isError ? null : formatAmount(nextBatchTotal, "CRC")}
         />
-        {upcoming.length > 0 && (
+        {topThree.length > 0 && (
           <ul className="space-y-0.5 text-xs text-muted-foreground">
-            {upcoming.map((p) => (
+            {topThree.map((p) => (
               <li key={p.id} className="flex justify-between gap-2">
                 <span className="truncate">{p.merchant}</span>
                 <span data-sensitive className="font-mono shrink-0">
                   {formatShortDate(p.next_cuota_date!)} ·{" "}
-                  {formatAmount(p.installment_amount, p.currency)}
+                  {formatAmount(nextCuotaOf(p), p.currency)}
                 </span>
               </li>
             ))}