feat(bisaya-course): update German course creation script to support default owner retrieval

- Modified the create-german-for-bisaya-course.js script to allow optional ownerHashedId parameter.
- Implemented a new function to find a default owner ('system' or 'admin') if no ownerHashedId is provided.
- Updated documentation to reflect the change in usage for the script.

backend/scripts/create-german-for-bisaya-course.js

@@ -3,7 +3,7 @@
  * Erstellt den Phase-1-Deutschkurs für Bisaya-Lernende.
  *
  * Verwendung:
- * node backend/scripts/create-german-for-bisaya-course.js <ownerHashedId>
+ * node backend/scripts/create-german-for-bisaya-course.js [ownerHashedId]
  */
 
 import crypto from 'crypto';
@@ -56,10 +56,23 @@ async function getOwnerByHashedId(ownerHashedId) {
   return user;
 }
 
+async function findDefaultOwner() {
+  let user = await User.findOne({ where: { username: 'system' } });
+  if (!user) {
+    user = await User.findOne({ where: { username: 'admin' } });
+  }
+  if (!user) {
+    throw new Error('Weder system- noch admin-Benutzer gefunden');
+  }
+  return user;
+}
+
 async function createGermanForBisayaCourse(ownerHashedId) {
   await sequelize.authenticate();
 
-  const owner = await getOwnerByHashedId(ownerHashedId);
+  const owner = ownerHashedId
+    ? await getOwnerByHashedId(ownerHashedId)
+    : await findDefaultOwner();
   const germanLanguageId = await getLanguageId('Deutsch');
   const bisayaLanguageId = await getLanguageId('Bisaya');
 
@@ -131,11 +144,6 @@ async function createGermanForBisayaCourse(ownerHashedId) {
 if (import.meta.url === `file://${process.argv[1]}`) {
   const ownerHashedId = process.argv[2];
 
-  if (!ownerHashedId) {
-    console.error('Verwendung: node backend/scripts/create-german-for-bisaya-course.js <ownerHashedId>');
-    process.exit(1);
-  }
-
   createGermanForBisayaCourse(ownerHashedId)
     .then(() => process.exit(0))
     .catch((error) => {

docs/GERMAN_FOR_BISAYA_IMPLEMENTATION_SPEC.md

@@ -463,10 +463,12 @@ Die Phasen 1 bis 5 sind jetzt als technische Struktur angelegt:
 ### Neuer Kurs von Grund auf
 
 ```bash
-node backend/scripts/create-german-for-bisaya-course.js <ownerHashedId>
+node backend/scripts/create-german-for-bisaya-course.js [ownerHashedId]
 node backend/scripts/create-german-for-bisaya-course-content.js
 ```
 
+Ohne `ownerHashedId` nutzt das Skript automatisch zuerst `system`, sonst `admin` als Kursbesitzer.
+
 ### Bestehenden Kurs stufenweise erweitern
 
 ```bash