fix(teaching): retain local mastery when resuming a word draft

projects/xiaoshu-mobile/src/app/features/learning/learning-page.component.ts

@@ -1885,9 +1885,10 @@ export class LearningPageComponent implements OnInit, OnDestroy {
   }
 
   private saveLessonBatch(mode: 'draft' | 'open-draft' | 'confirm' | 'mastery', words: Word[]): Observable<LessonBatchResult> {
-    const batchId = String(this.storageGet('batchId') || crypto.randomUUID());
-    this.storageSet('batchId', batchId);
-    const version = Number(this.storageGet('batchVersion') || 0);
+    const opening = mode === 'open-draft';
+    const batchId = opening ? crypto.randomUUID() : String(this.storageGet('batchId') || crypto.randomUUID());
+    const version = opening ? 0 : Number(this.storageGet('batchVersion') || 0);
+    if (!opening) this.storageSet('batchId', batchId);
     const xxqs = words.map(w => ({GeneralID: w.wordId, Title: w.word, check: mode === 'confirm' || mode === 'mastery' ? this.reviewValue(w) : 0}));
     return this.api.post<LessonBatchResult>('stu_record_update_v2', {
       orderId: this.query('orderId') || this.query('id'), uid: this.session.student()?.userId,
@@ -1895,6 +1896,7 @@ export class LearningPageComponent implements OnInit, OnDestroy {
       requestKey: this.draft().command('batch:' + batchId + ':' + version + ':' + mode + ':' + JSON.stringify(xxqs)),
       addon: JSON.stringify({bindingId: this.query('bindingId'), xxqs}),
     }).pipe(map(({result}) => {
+      if (opening && !result.resumed) this.clearLearningStorage();
       this.storageSet('batchId', result.batchId || batchId);
       this.storageSet('batchVersion', result.batchVersion);
       if (result.learned !== undefined) this.lessonLearnedCount.set(Number(result.learned));
@@ -2241,7 +2243,6 @@ export class LearningPageComponent implements OnInit, OnDestroy {
 
   private beginSelectedFlow(chosen: Word[], mode: '' | 'newword' | 'history_word'): void {
     if (this.query('orderId') && !mode) {
-      this.clearLearningStorage();
       this.submitting.set(true);
       this.saveLessonBatch('open-draft', chosen).pipe(finalize(() => this.submitting.set(false))).subscribe({
         next: result => {