Complete billedToTenant server action implementation

Implemented full server-side persistence for the billedToTenant property:

- Extract billedToTenant from formData in updateOrAddBill action
- Add to MongoDB $set operations for updating existing bills
- Include in new bill creation with value from form
- Set default value (true) for bills added to subsequent months
- Handle undefined values from existing database records using destructuring defaults

This completes the feature - bills can now track whether they should be
paid by the tenant, with backward compatibility for existing data.

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

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

app/lib/actions/billActions.ts

@@ -145,6 +145,7 @@ export const updateOrAddBill = withUser(async (user:AuthenticatedUser, locationI
     } = validatedFields.data;
 
     const billPaid = formData.get('billPaid') === 'on';
+    const billedToTenant = formData.get('billedToTenant') === 'on';
     const barcodeImage = formData.get('barcodeImage')?.valueOf() as string;
 
     // update the bill in the mongodb
@@ -159,6 +160,7 @@ export const updateOrAddBill = withUser(async (user:AuthenticatedUser, locationI
         const mongoDbSet = billAttachment ? {
             "bills.$[elem].name": billName,
             "bills.$[elem].paid": billPaid,
+            "bills.$[elem].billedToTenant": billedToTenant,
             "bills.$[elem].attachment": billAttachment,
             "bills.$[elem].notes": billNotes,
             "bills.$[elem].payedAmount": payedAmount,
@@ -167,6 +169,7 @@ export const updateOrAddBill = withUser(async (user:AuthenticatedUser, locationI
         }: {
             "bills.$[elem].name": billName,
             "bills.$[elem].paid": billPaid,
+            "bills.$[elem].billedToTenant": billedToTenant,
             "bills.$[elem].notes": billNotes,
             "bills.$[elem].payedAmount": payedAmount,
             "bills.$[elem].barcodeImage": barcodeImage,
@@ -191,6 +194,7 @@ export const updateOrAddBill = withUser(async (user:AuthenticatedUser, locationI
             _id: (new ObjectId()).toHexString(),
             name: billName,
             paid: billPaid,
+            billedToTenant: billedToTenant,
             attachment: billAttachment,
             notes: billNotes,
             payedAmount,
@@ -254,6 +258,7 @@ export const updateOrAddBill = withUser(async (user:AuthenticatedUser, locationI
                                             _id: (new ObjectId()).toHexString(),
                                             name: billName,
                                             paid: false, // New bills in subsequent months are unpaid
+                                            billedToTenant: true, // Default to true for subsequent months
                                             attachment: null, // No attachment for subsequent months
                                             notes: billNotes,
                                             payedAmount: null,

app/ui/BillEditForm.tsx

@@ -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, attachment, notes, payedAmount: initialPayedAmount, barcodeImage: initialBarcodeImage } = bill ?? { _id:undefined, name:"", paid:false, billedToTenant:true, notes:"" };
+    const { _id: billID, name, paid, billedToTenant = true, attachment, notes, payedAmount: initialPayedAmount, barcodeImage: initialBarcodeImage } = bill ?? { _id:undefined, name:"", paid:false, notes:"" };
 
     const { yearMonth:{year: billYear, month: billMonth}, _id: locationID } = location;