Step F2：项目列表 & 当前项目上下文

frontend/src/components/Layout.vue

@@ -1,35 +1,44 @@
 <template>
-  <el-container class="layout">
-    <el-header class="header">
-      <div class="logo">CTMS</div>
-      <div class="user-info">
-        <span>{{ auth.user?.username }}</span>
-        <el-tag size="small" class="role">{{ auth.user?.role }}</el-tag>
-        <el-button size="small" type="danger" @click="onLogout">退出登录</el-button>
-      </div>
-    </el-header>
-    <el-container>
-      <el-aside width="200px" class="aside">
-        <el-menu router default-active="/home">
-          <el-menu-item index="/home">首页</el-menu-item>
-        </el-menu>
-      </el-aside>
-      <el-main>
-        <router-view />
-      </el-main>
-    </el-container>
+<el-container class="layout">
+  <el-header class="header">
+    <div class="logo">CTMS</div>
+    <div class="current-study" v-if="study.currentStudy">
+      <el-tag type="success" size="small">{{ study.currentStudy.name }}</el-tag>
+    </div>
+    <div class="user-info">
+      <StudySelector />
+      <span>{{ auth.user?.username }}</span>
+      <el-tag size="small" class="role">{{ auth.user?.role }}</el-tag>
+      <el-button size="small" type="danger" @click="onLogout">退出登录</el-button>
+    </div>
+  </el-header>
+  <el-container>
+    <el-aside width="200px" class="aside" v-if="study.currentStudy">
+      <el-menu router :default-active="$route.path">
+        <el-menu-item index="/home">首页</el-menu-item>
+        <el-menu-item index="/study/home">项目首页</el-menu-item>
+      </el-menu>
+    </el-aside>
+    <el-main>
+      <router-view />
+    </el-main>
   </el-container>
+</el-container>
 </template>
 
 <script setup lang="ts">
 import { useRouter } from "vue-router";
 import { useAuthStore } from "../store/auth";
+import { useStudyStore } from "../store/study";
+import StudySelector from "./StudySelector.vue";
 
 const auth = useAuthStore();
+const study = useStudyStore();
 const router = useRouter();
 
 const onLogout = () => {
   auth.logout();
+  study.clearCurrentStudy();
   router.push("/login");
 };
 </script>

frontend/src/components/StudySelector.vue

@@ -0,0 +1,32 @@
+<template>
+  <el-dropdown>
+    <span class="el-dropdown-link">
+      <el-tag size="small" type="info">
+        {{ study.currentStudy?.name || "未选择项目" }}
+      </el-tag>
+    </span>
+    <template #dropdown>
+      <el-dropdown-menu>
+        <el-dropdown-item @click="goSelect">切换项目</el-dropdown-item>
+        <el-dropdown-item @click="clearStudy">清除当前项目</el-dropdown-item>
+      </el-dropdown-menu>
+    </template>
+  </el-dropdown>
+</template>
+
+<script setup lang="ts">
+import { useRouter } from "vue-router";
+import { useStudyStore } from "../store/study";
+
+const router = useRouter();
+const study = useStudyStore();
+
+const goSelect = () => {
+  router.push("/studies");
+};
+
+const clearStudy = () => {
+  study.clearCurrentStudy();
+  router.push("/studies");
+};
+</script>