Step F2：项目列表 & 当前项目上下文

frontend/src/store/study.ts

@@ -0,0 +1,37 @@
+import { defineStore } from "pinia";
+import { ref } from "vue";
+import type { Study } from "../types/api";
+
+const STUDY_KEY = "ctms_current_study";
+
+export const useStudyStore = defineStore("study", () => {
+  const currentStudy = ref<Study | null>(null);
+
+  const setCurrentStudy = (study: Study) => {
+    currentStudy.value = study;
+    localStorage.setItem(STUDY_KEY, JSON.stringify(study));
+  };
+
+  const loadCurrentStudy = () => {
+    const raw = localStorage.getItem(STUDY_KEY);
+    if (raw) {
+      try {
+        currentStudy.value = JSON.parse(raw) as Study;
+      } catch {
+        currentStudy.value = null;
+      }
+    }
+  };
+
+  const clearCurrentStudy = () => {
+    currentStudy.value = null;
+    localStorage.removeItem(STUDY_KEY);
+  };
+
+  return {
+    currentStudy,
+    setCurrentStudy,
+    loadCurrentStudy,
+    clearCurrentStudy,
+  };
+});