feat: 完善视频学习进度缓存

完善新手导航和三大创作模块的视频完成缓存、未完成提示与学习进度计算，确保进度按实际学习资源完成情况更新。

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/views/film/midterm-shooting/on-site/time-lapse.vue

@@ -7,8 +7,10 @@ import QuestionQuiz, {
   type Question,
 } from '@/components/QuestionQuiz/QuestionQuiz.vue'
 import { getBackgroundImage, getPublicPath, IMAGE_PATHS } from '@/utils'
+import { useFilmStore } from '@/stores/modules/film'
 
 const router = useRouter()
+const filmStore = useFilmStore()
 
 // 延时拍摄视频 URL（占位，后续可替换）
 const timeLapseVideoUrl = getPublicPath(
@@ -57,6 +59,7 @@ const videoPlaying = ref(false) // 视频播放状态
 // 答题完成，进入交互三（视频）
 const handleQuestionsComplete = () => {
   showObserveStep.value = true
+  filmStore.markViewed('FilmOnsiteTimeLapse')
 }
 </script>
 
@@ -137,7 +140,7 @@ const handleQuestionsComplete = () => {
 
     <!-- 返回按钮 -->
     <ImgButton
-      class="absolute right-0 top-0 z-20"
+      class="absolute right-0 top-0 z-50"
       :image="IMAGE_PATHS.COMPONENTS.BACK"
       @click="handleBack"
     />