feat: Implement invoice generation and emailing functionality

- Added invoice generation logic using DomPDF.
- Integrated invoice data retrieval from the API.
- Implemented language determination for invoices based on customer data.
- Added options to email invoices to customers and admin.
- Included HTML output option for direct viewing in the browser.
- Ensured proper redirection and error handling throughout the process.

api/v2/get/history.php

@@ -136,10 +136,22 @@ else {
     $messages = $stmt->fetchAll(PDO::FETCH_ASSOC);
 }
 
+// Clean up nested JSON in description fields before final encoding
+if (!isset($criterias['totals']) || $criterias['totals'] != '') {
+    foreach ($messages as &$message) {
+        if (isset($message['description']) && is_string($message['description'])) {
+            $decoded = json_decode($message['description'], true);
+            if (json_last_error() === JSON_ERROR_NONE) {
+                $message['description'] = json_encode($decoded, JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES);
+            }
+        }
+    }
+}
+
 //------------------------------------------
 //JSON_ENCODE
 //------------------------------------------
-$messages = json_encode($messages, JSON_UNESCAPED_UNICODE);
+$messages = json_encode($messages, JSON_UNESCAPED_UNICODE | JSON_UNESCAPED_SLASHES);
 
 //Send results
 echo $messages;