Replace billedToTenant boolean with billedTo enum

Migrated from boolean checkbox to enum-based radio buttons for better
flexibility and clarity in tracking bill payment responsibility.

Changes:
- Added BilledTo enum with values 'tenant' and 'landlord'
- Replaced Bill.billedToTenant (boolean) with Bill.billedTo (enum)
- Updated BillEditForm to use radio buttons instead of checkbox
- Updated billActions to handle billedTo enum values
- Updated all display filtering to use enum comparison
- Updated printActions barcode filtering
- Updated translations for radio button labels (en/hr)

The billedTo property is optional for backward compatibility -
undefined values default to BilledTo.Tenant, maintaining current
behavior where only tenant bills are displayed and calculated.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

app/ui/LocationCard.tsx

@@ -3,7 +3,7 @@
 import { Cog8ToothIcon, PlusCircleIcon, ShareIcon } from "@heroicons/react/24/outline";
 import { FC } from "react";
 import { BillBadge } from "./BillBadge";
-import { BillingLocation } from "../lib/db-types";
+import { BilledTo, BillingLocation } from "../lib/db-types";
 import { formatYearMonth } from "../lib/format";
 import { formatCurrency } from "../lib/formatStrings";
 import Link from "next/link";
@@ -20,7 +20,7 @@ export const LocationCard:FC<LocationCardProps> = ({location: { _id, name, yearM
     const currentLocale = useLocale();
 
     // sum all the billAmounts (only for bills billed to tenant)
-    const monthlyExpense = bills.reduce((acc, bill) => (bill.paid && (bill.billedToTenant ?? true)) ? acc + (bill.payedAmount ?? 0) : acc, 0);
+    const monthlyExpense = bills.reduce((acc, bill) => (bill.paid && (bill.billedTo ?? BilledTo.Tenant) === BilledTo.Tenant) ? acc + (bill.payedAmount ?? 0) : acc, 0);
 
     const handleCopyLinkClick = () => {
         // copy URL to clipboard
@@ -40,7 +40,7 @@ export const LocationCard:FC<LocationCardProps> = ({location: { _id, name, yearM
                 <h2 className="card-title mr-[2em] text-[1rem]">{formatYearMonth(yearMonth)} {name}</h2>
                 <div className="card-actions">
                     {
-                        bills.filter(bill => bill.billedToTenant ?? true).map(bill => <BillBadge key={`${_id}-${bill._id}`} locationId={_id} bill={bill} />)
+                        bills.filter(bill => (bill.billedTo ?? BilledTo.Tenant) === BilledTo.Tenant).map(bill => <BillBadge key={`${_id}-${bill._id}`} locationId={_id} bill={bill} />)
                     }
                     <Link href={`/bill/${_id}/add`} className="tooltip" data-tip={t("add-bill-button-tooltip")}>
                         <PlusCircleIcon className="h-[1em] w-[1em] cursor-pointer text-2xl inline-block" /><span className="ml-1 text-xs ml-[0.2rem]">{t("add-bill-button-tooltip")}</span>