- Add Redis mget method and cache management improvements

- Update cache expiration times for `economicCustomerName` and `isBooked` objects
- Introduce `getCachedForMultipleObjects` for batch cache retrieval
- Optimize `isBooked` with optional caching and update to store results
- Implement `getCustomerNames` in `users_o` with caching for bulk name retrieval
- Refactor customer transaction handling in `InvoicingPeriodRoute` for efficiency
- Filter orders excluded from invoicing in `collected_order_invoices_o`

services/nginx/app/objects/orders_o.php

@@ -759,16 +759,29 @@ class orders_o extends db
     /**
      * @throws Exception
      */
-    public function isBooked(): bool
+    public function isBooked(bool $useCache = false): bool
     {
         $this->requireSelected();
+        // Check if we should use the cached value
+        if ($useCache) {
+            $cached = self::getCached('isBooked', $this->id);
+            if ($cached !== null) {
+                return (bool)$cached;
+            }
+        }
         // Check the invoice collection has been booked
         if ((int)$this->invoice_collection_id->value() > 0) {
             $invoice_collection = (new collected_order_invoices_o())->select((int)$this->invoice_collection_id->value());
             self::requireSelected();
-            return $invoice_collection->isBooked();
+            $isBooked = $invoice_collection->isBooked();
+            // Cache the result
+            self::cache('isBooked', $isBooked, $this->id);
+            self::setCachedExpiration('isBooked', self::$isBookedCacheExpiration, $this->id);
+            return $isBooked;
         } else {
             // If there is no invoice collection, the order is not booked
+            self::cache('isBooked', false, $this->id);
+            self::setCachedExpiration('isBooked', self::$isBookedCacheExpiration, $this->id);
             return false;
         }
     }