fix: hide admin buttons when viewing course package via 试看 preview

"试看" (preview) from the storefront should show a read-only view without
admin operations (编辑, 删除, 发布上架, 下架). Add preview=1 query param
to distinguish preview from direct management navigation. Also limit
previewable sections to first one in preview mode, consistent with
non-owner experience.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/components/course-package-store.vue

@@ -107,7 +107,7 @@ export default defineComponent({
 
     const onPreview = (pkg: CoursePackage) => {
       if (isLoggedIn()) {
-        router.push(`/course/course-package/detail?id=${pkg.id}`);
+        router.push(`/course/course-package/detail?id=${pkg.id}&preview=1`);
       } else {
         showDialog({
           title: '提示',

src/pages/qumu/course-package/detail.vue

@@ -42,7 +42,7 @@
         </div>
       </div>
     </div>
-    <div class="footer" v-if="isOwner">
+    <div class="footer" v-if="isOwner && !isPreview">
       <van-button v-if="!isActive" type="primary" @click="onEdit">编辑</van-button>
       <van-button v-if="!isActive" type="danger" @click="onDelete">删除</van-button>
       <van-button v-if="!isActive" type="success" @click="onPublish">发布上架</van-button>
@@ -87,6 +87,7 @@ export default defineComponent({
       if (!pkg.value?.created_by || !userStore.current?.hty_id) return false;
       return pkg.value.created_by === userStore.current.hty_id;
     });
+    const isPreview = computed(() => route.query.preview === '1');
 
     const loadData = async () => {
       const id = route.query.id as string;
@@ -173,7 +174,7 @@ export default defineComponent({
 
     const isPreviewable = (section: CourseSection) => {
       if (!section.id) return false;
-      if (isOwner.value) return true;
+      if (isOwner.value && !isPreview.value) return true;
       return section.id === firstSectionId.value;
     };
 
@@ -192,7 +193,7 @@ export default defineComponent({
     onMounted(loadData);
 
     return {
-      pkg, courseGroups, loading, isActive, isPublished, isOwner, isLoggedIn,
+      pkg, courseGroups, loading, isActive, isPublished, isOwner, isLoggedIn, isPreview,
       onEdit, onDelete, onPublish, onUnpublish, previewSection, goBack,
       isPreviewable, handleSectionClick,
     };