fix(customers): the customer file's balances are the statement's balances

The /clientes/:id ledger card is titled "Estado de cuenta" and links straight to
the statement, but its per-line tiles came from a groupBy with `voidedAt: null`
and nothing else — no balance floor, no source exclusion, no outstanding rule.
It was a raw lifetime sum, double-counting the pre-cutover history that each
BALANCE FORWARD row already absorbs, and the card said so in its own footnote
rather than being fixed.

Importing prior periods turned that from wrong into badly wrong. Every closed
year is now also held as its own tagged copy, so an unfloored sum adds each one
a second time on top of the opening balance that contains it. NUMid 501 read
-7,119.29 before the archives landed and -15,270.59 after, against a true
-10,715.29 — the gap being exactly the 2024 and 2025 closing balances.

The tiles now take the same three rules the statement takes, and agree with it
for all 600 customers sampled.

Two places needed the archives excluded explicitly, because the balance floor
does not do it:

  - A customer whose newest BALANCE FORWARD lives inside an archive floors at
    that archive's own January 1, so every row of it clears the floor. One
    customer, 28 rows.
  - The archives are not cleanly bounded. datos2@2024 carries rows dated 2022,
    2023, 2025 and one in 2026; datos2@2025 two more. Those clear any floor and
    land in the current year next to the live ledger's own copy of them.

That second point is a defect in 93f8171, not only in this card: statement()
and the edo-cuenta-datos report were both filtering the current period by
source and date without excluding the period tags, so four customers on the
dev book would have read a closed year's rows as current. Both are fixed here.
The portal already had it right.

The year's movement list on the card keeps showing every non-archive row, as
before — it is a list of what happened, not a balance.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

apps/web/src/app/clientes/[id]/page.tsx

@@ -809,7 +809,8 @@ function EstadoCuentaSection({
         )}
         <div className="section-note" style={{ padding: "0 16px 14px" }}>
           Movimientos de {year}, del más antiguo al más reciente. Los saldos de
-          arriba son el acumulado histórico, no el del año.
+          arriba son el saldo actual por línea de negocio — los mismos del
+          estado de cuenta, no la suma del año.
         </div>
       </div>
       {transactions.length > 0 && (