Bills: fix Record Payment dialog overflow

The 'Apply existing payment' candidate list spilled outside the dialog.
Cap the dialog at max-h-[85vh] with overflow-y-auto and drop the list's
nested scroll so the whole dialog scrolls as one and stays contained.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/pages/accounting/AccountingBillsPage.tsx

@@ -933,7 +933,7 @@ export default function AccountingBillsPage() {
 
       {/* Payment dialog */}
       <Dialog open={!!payBill} onOpenChange={(o) => !o && setPayBill(null)}>
-        <DialogContent className="max-w-lg">
+        <DialogContent className="max-w-lg max-h-[85vh] overflow-y-auto">
           <DialogHeader>
             <DialogTitle>Record payment {payBill ? `· Bill ${payBill.number}` : ""}</DialogTitle>
           </DialogHeader>
@@ -960,7 +960,7 @@ export default function AccountingBillsPage() {
                   <div className="text-xs text-muted-foreground">
                     Pick a bank payment already in the register to settle this bill — no new withdrawal is created. Same-vendor and exact-amount matches are listed first.
                   </div>
-                  <div className="max-h-72 overflow-y-auto rounded-md border divide-y">
+                  <div className="rounded-md border divide-y">
                     {(() => {
                       const bal = Number(payBill.balance);
                       const cands = [...(unmatchedPayments as any[])].sort((a, b) => {