Fix payment display and dashboard refresh functionality

- Fix 'paid in full for others' payments showing CHF 0.00 instead of actual amount
- Add time-based sorting to payments (date + createdAt) for proper chronological order
- Redirect to dashboard after adding payment instead of payments list
- Implement complete dashboard refresh after payment deletion via modal
- Fix dashboard component reactivity for single debtor view updates

src/routes/api/cospend/balance/+server.ts

@@ -66,7 +66,7 @@ export const GET: RequestHandler = async ({ locals, url }) => {
           }
         },
         { $unwind: '$paymentId' },
-        { $sort: { 'paymentId.date': -1 } },
+        { $sort: { 'paymentId.date': -1, 'paymentId.createdAt': -1 } },
         { $limit: 10 }
       ]);