fix: 修复课程运行时初始化与拖拽测试

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/utils/yiban.ts

@@ -40,6 +40,45 @@ function warnVideoAjaxUnavailable(description: string) {
 	});
 }
 
+/**
+ * 从 URL 参数初始化易班会话状态
+ * 在 React 渲染前调用，确保页面首次读取进度时 courseId / userId 已写入 store
+ */
+export function initializeYibanSession() {
+	const params = new URLSearchParams(window.location.search);
+	const courseId = params.get("courseId") ?? params.get("courseid");
+	const uid = params.get("uid");
+	const forceYiban = params.get("yiban") === "1";
+	const hasYibanParams = !!(courseId || uid);
+	const hasVideoAjax = isVideoAjaxAvailable();
+	const isYibanEnv = import.meta.env.DEV
+		? hasYibanParams && forceYiban
+		: hasYibanParams;
+	const storageMode = isYibanEnv && hasVideoAjax ? "yiban" : "session";
+	const userStore = useUserStore.getState();
+
+	userStore.setYibanConnectionStatus(
+		storageMode === "yiban" ? "connected" : "disconnected",
+	);
+	if (courseId) userStore.setCourseId(courseId);
+	if (uid) userStore.setUserInfo({ userId: uid });
+
+	console.info(
+		storageMode === "yiban"
+			? "[yiban] initialized"
+			: "[yiban] use session storage fallback",
+		{
+			courseId,
+			uid,
+			isDev: import.meta.env.DEV,
+			forceYiban,
+			hasYibanParams,
+			hasVideoAjax,
+			storageMode,
+		},
+	);
+}
+
 /**
  * 获取 VideoAjax 实例
  */
@@ -228,10 +267,7 @@ export async function getUserStorage(
 
 	if (backend === "session") {
 		const itemValue = sessionStorage.getItem(getStorageKey(lessonId, key));
-		return itemValue === undefined ||
-			itemValue === null ||
-			itemValue === "null" ||
-			itemValue === ""
+		return itemValue === null || itemValue === "null" || itemValue === ""
 			? { status: "empty", content: "" }
 			: { status: "success", content: itemValue };
 	}
@@ -466,6 +502,7 @@ export async function saveUserAnswer(params: {
 		return false;
 	}
 
+	// 易班 API 以 getUserAnswer 写入答题记录，方法名与「保存」语义相反，属平台既有命名
 	const result = await yibanStatusRequest<unknown>({
 		method: (callback) =>
 			getVideoAjax().getUserAnswer(