feat(deploy): add vocab course change detection and sync step

- Implemented a new workflow step to detect changes in vocab course files and conditionally sync content.
- Added a script to check for specific changes in the repository and trigger the sync process if necessary.
- Introduced a new npm script for syncing vocab course content in the backend package.json.

backend/package.json

@@ -14,6 +14,7 @@
     "cleanup-connections": "node cleanup-connections.js",
     "diag:town-worth": "QUIET_ENV_LOGS=1 DOTENV_CONFIG_QUIET=1 node scripts/falukant-town-product-worth-stats.mjs",
     "diag:moneyflow": "QUIET_ENV_LOGS=1 DOTENV_CONFIG_QUIET=1 node scripts/falukant-moneyflow-report.mjs",
+    "sync:vocab-courses": "node scripts/sync-vocab-course-content.js",
     "lockfile:sync": "npm install --package-lock-only",
     "test": "echo \"Error: no test specified\" && exit 1"
   },

backend/scripts/sync-vocab-course-content.js

@@ -0,0 +1,105 @@
+#!/usr/bin/env node
+/**
+ * Synchronisiert Kursstruktur und generierte Übungen nach Kursänderungen.
+ *
+ * Dieses Script ist für CI/CD gedacht und darf keinen Lernfortschritt löschen.
+ * Es führt bewusst nicht apply-bisaya-course-refresh.js aus, weil dieses Script
+ * Lektions- und Übungsfortschritte zurücksetzt.
+ *
+ * Verwendung:
+ *   node backend/scripts/sync-vocab-course-content.js
+ *   node backend/scripts/sync-vocab-course-content.js --scope=bisaya
+ *   node backend/scripts/sync-vocab-course-content.js --scope=german-for-bisaya
+ *   VOCAB_COURSE_SYNC_DRY_RUN=1 node backend/scripts/sync-vocab-course-content.js
+ */
+
+import { spawn } from 'child_process';
+import path from 'path';
+import { fileURLToPath } from 'url';
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
+const repoRoot = path.resolve(__dirname, '../..');
+
+const SAFE_SYNC_STEPS = {
+  bisaya: [
+    'backend/scripts/migrate-bisaya-zahlen-split.js',
+    'backend/scripts/update-bisaya-didactics.js',
+    'backend/scripts/extend-bisaya-course-phase3.js',
+    'backend/scripts/extend-bisaya-course-phase4.js',
+    'backend/scripts/extend-bisaya-course-phase5.js',
+    'backend/scripts/create-bisaya-course-content.js'
+  ],
+  'german-for-bisaya': [
+    'backend/scripts/extend-german-for-bisaya-course-phase3.js',
+    'backend/scripts/extend-german-for-bisaya-course-phase4.js',
+    'backend/scripts/extend-german-for-bisaya-course-phase5.js',
+    'backend/scripts/create-german-for-bisaya-course-content.js'
+  ]
+};
+
+function parseScopes() {
+  const scopeArg = process.argv.find((arg) => arg.startsWith('--scope='));
+  const rawScope = scopeArg?.slice('--scope='.length) || process.env.VOCAB_COURSE_SYNC_SCOPE || 'all';
+  const requested = rawScope
+    .split(',')
+    .map((entry) => entry.trim())
+    .filter(Boolean);
+
+  if (requested.length === 0 || requested.includes('all')) {
+    return Object.keys(SAFE_SYNC_STEPS);
+  }
+
+  const unknownScopes = requested.filter((scope) => !SAFE_SYNC_STEPS[scope]);
+  if (unknownScopes.length > 0) {
+    throw new Error(`Unbekannter Kurs-Sync-Scope: ${unknownScopes.join(', ')}`);
+  }
+
+  return requested;
+}
+
+function runNodeScript(scriptPath) {
+  return new Promise((resolve, reject) => {
+    const child = spawn(process.execPath, [scriptPath], {
+      cwd: repoRoot,
+      env: process.env,
+      stdio: 'inherit'
+    });
+
+    child.on('error', reject);
+    child.on('exit', (code, signal) => {
+      if (code === 0) {
+        resolve();
+        return;
+      }
+      reject(new Error(`${scriptPath} beendet mit ${signal || `Exit-Code ${code}`}`));
+    });
+  });
+}
+
+async function main() {
+  const scopes = parseScopes();
+  const dryRun = process.env.VOCAB_COURSE_SYNC_DRY_RUN === '1' || process.argv.includes('--dry-run');
+  const steps = scopes.flatMap((scope) => SAFE_SYNC_STEPS[scope]);
+
+  console.log('Vokabelkurs-Sync');
+  console.log(`Scopes: ${scopes.join(', ')}`);
+  console.log(`Schritte: ${steps.length}`);
+
+  for (const step of steps) {
+    console.log(`\n→ ${step}`);
+    if (dryRun) continue;
+    await runNodeScript(step);
+  }
+
+  if (dryRun) {
+    console.log('\nDry-Run abgeschlossen. Es wurden keine Scripts ausgeführt.');
+  } else {
+    console.log('\nVokabelkurs-Sync abgeschlossen.');
+  }
+}
+
+main().catch((error) => {
+  console.error('Vokabelkurs-Sync fehlgeschlagen:', error);
+  process.exit(1);
+});