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/BillEditForm.tsx

@@ -1,7 +1,7 @@
 "use client";
 
 import { DocumentIcon, TrashIcon } from "@heroicons/react/24/outline";
-import { Bill, BillingLocation } from "../lib/db-types";
+import { Bill, BilledTo, BillingLocation } from "../lib/db-types";
 import React, { FC } from "react";
 import { useFormState } from "react-dom";
 import { updateOrAddBill } from "../lib/actions/billActions";
@@ -29,7 +29,7 @@ export const BillEditForm:FC<BillEditFormProps> = ({ location, bill }) => {
     const t = useTranslations("bill-edit-form");
     const locale = useLocale();
 
-    const { _id: billID, name, paid, billedToTenant = true, attachment, notes, payedAmount: initialPayedAmount, barcodeImage: initialBarcodeImage } = bill ?? { _id:undefined, name:"", paid:false, notes:"" };
+    const { _id: billID, name, paid, billedTo = BilledTo.Tenant, attachment, notes, payedAmount: initialPayedAmount, barcodeImage: initialBarcodeImage } = bill ?? { _id:undefined, name:"", paid:false, notes:"" };
 
     const { yearMonth:{year: billYear, month: billMonth}, _id: locationID } = location;
 
@@ -40,14 +40,14 @@ export const BillEditForm:FC<BillEditFormProps> = ({ location, bill }) => {
     const [ isScanningPDF, setIsScanningPDF ] = React.useState<boolean>(false);
     const [ state, dispatch ] = useFormState(handleAction, initialState);
     const [ isPaid, setIsPaid ] = React.useState<boolean>(paid);
-    const [ isBilledToTenant, setIsBilledToTenant ] = React.useState<boolean>(billedToTenant);
+    const [ billedToValue, setBilledToValue ] = React.useState<BilledTo>(billedTo);
     const [ payedAmount, setPayedAmount ] = React.useState<string>(initialPayedAmount ? `${initialPayedAmount/100}` : "" );
     const [ barcodeImage, setBarcodeImage ] = React.useState<string | undefined>(initialBarcodeImage);
     const [ barcodeResults, setBarcodeResults ] = React.useState<Array<DecodeResult> | null>(null);
 
 
-    const billedToTenant_handleChange = (event: React.ChangeEvent<HTMLInputElement>) => {
-        setIsBilledToTenant(event.target.checked);
+    const billedTo_handleChange = (event: React.ChangeEvent<HTMLInputElement>) => {
+        setBilledToValue(event.target.value as BilledTo);
     }
 
     const billPaid_handleChange = (event: React.ChangeEvent<HTMLInputElement>) => {
@@ -209,10 +209,33 @@ export const BillEditForm:FC<BillEditFormProps> = ({ location, bill }) => {
                 </div>
 
                 <div className="form-control mt-4">
-                    <label className="label cursor-pointer">
-                        <span className="label-text">{t("billed-to-tenant")}</span> 
-                        <input type="checkbox" name="billedToTenant" className="toggle toggle-primary" checked={isBilledToTenant} onChange={billedToTenant_handleChange} />
+                    <label className="label">
+                        <span className="label-text">{t("billed-to-label")}</span>
                     </label>
+                    <div className="flex gap-4">
+                        <label className="label cursor-pointer gap-2">
+                            <input 
+                                type="radio" 
+                                name="billedTo" 
+                                value={BilledTo.Tenant}
+                                className="radio radio-primary" 
+                                checked={billedToValue === BilledTo.Tenant} 
+                                onChange={billedTo_handleChange} 
+                            />
+                            <span className="label-text">{t("billed-to-tenant-option")}</span>
+                        </label>
+                        <label className="label cursor-pointer gap-2">
+                            <input 
+                                type="radio" 
+                                name="billedTo" 
+                                value={BilledTo.Landlord}
+                                className="radio radio-primary" 
+                                checked={billedToValue === BilledTo.Landlord} 
+                                onChange={billedTo_handleChange} 
+                            />
+                            <span className="label-text">{t("billed-to-landlord-option")}</span>
+                        </label>
+                    </div>
                 </div>
 
                 {/* Show toggle only when adding a new bill (not editing) */}