Add seenByTenant tracking feature

- Add seenByTenant field to BillingLocation interface
- Implement setSeenByTenant function to mark locations as viewed by tenant
  - Checks if flag is already set to avoid unnecessary DB updates
  - Includes TypeDoc documentation
- Update LocationViewPage to call setSeenByTenant when non-owner visits
- Add seenByTenant to fetchAllLocations projection
- Update LocationCard to show "seen by tenant" status indicator
  - Displays in "Monthly statement" fieldset with checkmark icon
  - Shows alongside monthly expense total
- Add localization strings for monthly statement and seen status

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

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

app/ui/LocationCard.tsx

@@ -1,6 +1,6 @@
 'use client';
 
-import { Cog8ToothIcon, PlusCircleIcon, ShareIcon } from "@heroicons/react/24/outline";
+import { CheckCircleIcon, Cog8ToothIcon, PlusCircleIcon, ShareIcon, BanknotesIcon } from "@heroicons/react/24/outline";
 import { FC } from "react";
 import { BillBadge } from "./BillBadge";
 import { BillingLocation } from "../lib/db-types";
@@ -14,7 +14,10 @@ export interface LocationCardProps {
     location: BillingLocation
 }
 
-export const LocationCard:FC<LocationCardProps> = ({location: { _id, name, yearMonth, bills }}) => {
+export const LocationCard:FC<LocationCardProps> = ({location}) => {
+    const { _id, name, yearMonth, bills, seenByTenant } = location;
+
+    console.log("seenByTenant:", seenByTenant);
 
     const t = useTranslations("home-page.location-card");
     const currentLocale = useLocale();
@@ -46,12 +49,27 @@ export const LocationCard:FC<LocationCardProps> = ({location: { _id, name, yearM
                         <PlusCircleIcon className="h-[1em] w-[1em] cursor-pointer text-2xl inline-block" /><span className="text-xs ml-[0.2rem] mr-[3rem]">{t("add-bill-button-tooltip")}</span>
                     </Link>
                 </div>
-                {
-                    monthlyExpense > 0 ?
-                    <p>
-                        { t("payed-total-label") } <strong>${formatCurrency(monthlyExpense)}</strong>
-                    </p>
-                    : null
+
+
+                    { monthlyExpense > 0 || seenByTenant ?
+
+                    <fieldset className="card card-compact card-bordered border-1 border-neutral p-3 mt-2 mr-20">
+                        <legend className="fieldset-legend px-2 text-sm font-semibold uppercase">{t("monthly-statement-legend")}</legend>
+                        {
+                            monthlyExpense > 0 ?
+                            <div className="flex items-center gap-2">
+                                <BanknotesIcon className="h-5 w-5" />
+                                { t("payed-total-label") } <strong>${formatCurrency(monthlyExpense)}</strong>
+                            </div>
+                            : null
+                        }
+                        {seenByTenant && (
+                            <div className="flex items-center gap-2 mt-2">
+                                <CheckCircleIcon className="h-5 w-5 text-success" />
+                                <span className="text-sm">{t("seen-by-tenant-label")}</span>
+                            </div>
+                        )}
+                    </fieldset> : null
                 }
 
                 <ShareIcon className="h-[1em] w-[1em] cursor-pointer text-2xl inline-block hover:text-red-500" title="create sharable link" style={{ position: "absolute", bottom: ".6em", right: "1.2em" }} onClick={handleCopyLinkClick} />