feat(finance): connection-based balances + lump-sum payment recording

Klinik-laboratuvar finance in TR is dönemsel, not job-by-job. Forcing
the lab to mark each finance_entry as paid was unrealistic — labs get a
single 50.000 TL transfer covering twelve jobs and don't want to walk a
list. Reworked the page around connection balances and free-amount
payments.

Data model
  - New 'payments' table:
      tenantId             whose ledger it lives in
      counterpartTenantId  the other side of the transaction
      direction            inflow (lab received) | outflow (clinic paid)
      amount, currency, paymentDate
      method               cash | bank | card | check | other
      notes, recordedBy
    Indexes: (tenantId, counterpartTenantId), paymentDate DESC. Permission:
    both teams can read, only owners/admins of the recording side can
    update or delete.

Server
  - recordPaymentAction: requires owner/admin, verifies an approved
    connection exists between (lab, clinic), then writes a single row.
    Direction is inferred from the caller's tenant kind so a lab can
    never accidentally book an outflow.
  - deletePaymentAction: same auth, tenant-scoped delete.
  - listPayments(tenantId) + computeBalancesByCounterpart({ kind,
    entries, payments }): one pass over both ledgers, returns
    [{ counterpartTenantId, invoiced, paid, open, lastPaymentAt }]
    sorted by open desc. invoiced pulls from finance_entries (receivable
    for lab, debt for clinic); paid pulls from the new payments table.

UI
  - /finance now leads with a Bakiye kartı: a row per connected
    counterpart showing invoiced, paid, last payment date and the open
    amount tinted green (lab alacak) or red (clinic borç), each with an
    inline 'Ödeme Al' / 'Ödeme Yap' button.
  - RecordPaymentDialog: amount (defaults to the open balance, lump
    sums obviously not pre-filled with a specific entry), date,
    currency, method (Nakit/Banka/Kart/Çek/Diğer), free-text note.
    Posts to recordPaymentAction, refresh on success.
  - Stat cards reworked: Toplam Açık Alacak/Borç and Tahsil Edilen /
    Ödenen replaced the old pending-totals so the headline numbers
    actually reflect the new flow.

Existing finance_entries (job-driven receivables/debts) remain the
single source of truth for 'how much was invoiced'; the new table tracks
'how much was actually collected'. Open balance = invoiced - paid, always
computed live — no individual entry needs to be marked 'paid' anymore.

src/app/(dashboard)/finance/components/balances-card.tsx

@@ -0,0 +1,100 @@
+import { Card, CardContent, CardDescription, CardHeader, CardTitle } from "@/components/ui/card";
+import type { CounterpartBalance } from "@/lib/appwrite/payment-queries";
+import { RecordPaymentDialog } from "./record-payment-dialog";
+
+function formatMoney(amount: number, currency: string): string {
+  try {
+    return new Intl.NumberFormat("tr-TR", { style: "currency", currency }).format(amount);
+  } catch {
+    return `${amount.toFixed(2)} ${currency}`;
+  }
+}
+
+const dateFormatter = new Intl.DateTimeFormat("tr-TR", {
+  day: "2-digit",
+  month: "2-digit",
+  year: "numeric",
+});
+
+export function BalancesCard({
+  balances,
+  counterpartNames,
+  selfKind,
+  defaultCurrency,
+}: {
+  balances: CounterpartBalance[];
+  counterpartNames: Record<string, string>;
+  selfKind: "lab" | "clinic";
+  defaultCurrency: string;
+}) {
+  const isLab = selfKind === "lab";
+  return (
+    <Card>
+      <CardHeader>
+        <CardTitle>{isLab ? "Klinik Bakiyeleri" : "Laboratuvar Bakiyeleri"}</CardTitle>
+        <CardDescription>
+          {isLab
+            ? "Her klinik için açık bakiye ve son tahsilatlar. Toplu ödemeleri buradan girebilirsiniz."
+            : "Çalıştığınız her laboratuvar için açık bakiye ve son ödemeleriniz."}
+        </CardDescription>
+      </CardHeader>
+      <CardContent>
+        {balances.length === 0 ? (
+          <p className="text-muted-foreground py-6 text-center text-sm">
+            Bağlantılarınız için henüz finansal hareket yok.
+          </p>
+        ) : (
+          <ul className="divide-y rounded-md border">
+            {balances.map((b) => {
+              const name = counterpartNames[b.counterpartTenantId] ?? "—";
+              const settled = b.open <= 0.01;
+              return (
+                <li
+                  key={b.counterpartTenantId}
+                  className="flex flex-wrap items-center gap-3 px-3 py-3"
+                >
+                  <div className="min-w-0 flex-1">
+                    <p className="truncate font-medium">{name}</p>
+                    <p className="text-muted-foreground text-xs">
+                      Fatura: {formatMoney(b.invoiced, b.currency)} · Ödenen:{" "}
+                      {formatMoney(b.paid, b.currency)}
+                      {b.lastPaymentAt && (
+                        <>
+                          {" "}· Son ödeme:{" "}
+                          {dateFormatter.format(new Date(b.lastPaymentAt))}
+                        </>
+                      )}
+                    </p>
+                  </div>
+                  <div className="text-right">
+                    <p
+                      className={`text-base font-semibold tabular-nums ${
+                        settled
+                          ? "text-muted-foreground"
+                          : isLab
+                            ? "text-emerald-600 dark:text-emerald-400"
+                            : "text-rose-600 dark:text-rose-400"
+                      }`}
+                    >
+                      {formatMoney(b.open, b.currency)}
+                    </p>
+                    <p className="text-muted-foreground text-xs">
+                      {settled ? "Kapalı" : isLab ? "Açık alacak" : "Açık borç"}
+                    </p>
+                  </div>
+                  <RecordPaymentDialog
+                    counterpartTenantId={b.counterpartTenantId}
+                    counterpartName={name}
+                    selfKind={selfKind}
+                    defaultCurrency={b.currency || defaultCurrency}
+                    openAmount={b.open > 0 ? b.open : undefined}
+                  />
+                </li>
+              );
+            })}
+          </ul>
+        )}
+      </CardContent>
+    </Card>
+  );
+}