fix: update bill detail page to support combined shareId

Changes:
- Extract shareId (40 chars) and billID from combined URL parameter
- Validate shareId using validateShareAccess before fetching bill
- Pass shareId to ViewBillCard for secure uploads
- Show error message if share link is invalid or expired

URL format: /share/bill/{shareId}-{billID}
  where shareId = locationId (24) + checksum (16) = 40 chars

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

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

app/[locale]/share/bill/[id]/page.tsx

@@ -2,19 +2,40 @@ import { fetchBillById } from '@/app/lib/actions/billActions';
 import { ViewBillCard } from '@/app/ui/ViewBillCard';
 import { Main } from '@/app/ui/Main';
 import { notFound } from 'next/navigation';
+import { validateShareAccess } from '@/app/lib/actions/locationActions';
 
-export default async function Page({ params:{ id } }: { params: { id:string } }) {
+export default async function Page({ params: { id } }: { params: { id: string } }) {
 
-    const [locationID, billID] = id.split('-');
+    // Split combined ID: shareId (40 chars) + '-' + billID (24 chars)
+    // ShareId = locationId (24) + checksum (16) = 40 chars
+    const shareId = id.substring(0, 40);
+    const billID = id.substring(41); // Skip the '-' separator
 
+    // Validate share access (checks checksum + TTL, extracts locationId)
+    const accessValidation = await validateShareAccess(shareId);
+
+    if (!accessValidation.valid || !accessValidation.locationId) {
+        return (
+            <Main>
+                <div className="alert alert-error">
+                    <p>{accessValidation.error || 'This content is no longer shared'}</p>
+                </div>
+            </Main>
+        );
+    }
+
+    const locationID = accessValidation.locationId;
+
+    // Fetch bill data
     const [location, bill] = await fetchBillById(locationID, billID) ?? [];
 
     if (!bill || !location) {
-        return(notFound());
+        return notFound();
     }
+
     return (
         <Main>
-            <ViewBillCard location={location} bill={bill} />
+            <ViewBillCard location={location} bill={bill} shareId={shareId} />
         </Main>
     );
 }