Return 200+null instead of 404 when no cash up found for date — eliminates browser console error

backend/src/routes/cashup.js

@@ -12,7 +12,7 @@ export async function cashupRoutes(app) {
     const { rows } = await pool.query(
       'SELECT * FROM cash_ups WHERE session_date = $1', [date]
     )
-    if (!rows.length) return reply.status(404).send({ error: 'Not found' })
+    if (!rows.length) return { cash_up: null }
 
     const cashUp = rows[0]
     const [denoms, machines, recon, attachments] = await Promise.all([