fix: useEffect anti-patterns, attendance permissions, and received-invoices schema mismatch

- Remove ref-mirror useEffect in AuthContext (cachedUserRef already written at mutation sites)
- Replace useEffect slide direction in ReceivedInvoices with render-time computation
- Fix Login.tsx useEffect dependency array (mount-only alert should have [] deps)
- Move "project created" alert to navigation source in ProjectCreate, remove useEffect in ProjectDetail
- Move companySettings defaults into fetch callbacks in InvoiceDetail and OfferDetail
- Replace due_date useEffect with useMemo in InvoiceDetail
- Capture initial snapshots from API data instead of useEffect in InvoiceDetail, OfferDetail, OrderDetail
- Replace localStorage draft useEffect with lazy useState initializer in OfferDetail
- Fix attendance dropdown to filter by attendance.record permission only
- Fix clock-out 404 on update-address (remove departure_time filter for departure action)
- Fix received-invoices stats endpoint referencing non-existent is_deleted and amount_czk columns

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/admin/pages/Login.tsx

@@ -34,7 +34,8 @@ export default function Login() {
     } else if (shouldShowLogoutAlert()) {
       alert.success("Byli jste úspěšně odhlášeni.");
     }
-  }, [alert]);
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, []);
 
   // Auto-focus TOTP input
   useEffect(() => {