fix: enhance priority handling in sort-config and JiraService

- Added a fallback mechanism in getPriorityValue to default to 'medium' when an unknown priority is encountered, improving robustness.
- Updated priority mapping in JiraService to change 'Highest' to 'urgent', aligning with new priority definitions.

lib/sort-config.ts

@@ -106,7 +106,12 @@ function compareValues<T>(a: T, b: T, direction: SortDirection): number {
  * Obtient la valeur de priorité numérique pour le tri
  */
 function getPriorityValue(priority: TaskPriority): number {
-  return getPriorityConfig(priority).order;
+  const config = getPriorityConfig(priority);
+  if (!config) {
+    console.warn(`⚠️ Priorité inconnue: ${priority}, utilisation de 'medium' par défaut`);
+    return getPriorityConfig('medium').order;
+  }
+  return config.order;
 }
 
 /**