feat(speaking): fetch dialogue defaults on config page mount

src/views/Editor/EnglishSpeaking/preview/TopicDiscussionPreview.vue

@@ -98,7 +98,7 @@
 import { ref, computed, watch, onMounted, onUnmounted, inject } from 'vue'
 import type { DialogueReport, OverallEvaluation, PreviewAIRole, PreviewDialogueState, SessionStartInfo, VideoMeta } from '@/types/englishSpeaking'
 import { useSpeakingStore } from '@/store/speaking'
-import { getSpeakingConfig } from '@/services/speaking'
+import { getSpeakingConfig, getDialogueDefaults } from '@/services/speaking'
 import { createDialogueApi, DialogueApiError } from '../services/llmService'
 
 import DialogueChatView from './DialogueChatView.vue'
@@ -537,7 +537,13 @@ watch(() => props.configId, (id) => {
   loadConfigFromBackend(id)
 })
 
-onMounted(() => {
+onMounted(async () => {
+  try {
+    const defaults = await getDialogueDefaults()
+    speakingStore.hydrateDefaults(defaults)
+  } catch (err) {
+    console.error('[speaking] failed to load dialogue defaults', err)
+  }
   speakingStore.setPreviewState(dialogueState.value)
   loadConfigFromBackend(props.configId)
   if (fitWrapperRef.value) {