feat(预期)：学习预期闭环 + 权重配置 UI

- StartTask：新会话强制填写学习预期（不可跳过），页面顶部常驻展示可修改
- 结束会话弹窗：展示本次预期供对照，有残片时自动拉取 AI 聚合草稿作为编辑起点
- Study：常用操作增加权重配置——五维度滑块、合计校验 100%、保存后重算并刷新
- api：expectation / report-draft / priority-weights 接口

src/components/StartTask.vue

@@ -11,6 +11,7 @@ import {
 } from "@/api/studySessions";
 import { useStudyFragment } from "@/components/composables/fragment";
 import { getFragmentsBySession, updateFragments } from "@/api/reportFragments";
+import { getExpectation, getReportDraft, upsertExpectation } from "@/api/studySessions";
 import router from "@/router";
 
 const {
@@ -23,6 +24,13 @@ const {
 
 const summaryDialogVisible = ref(false);
 const summaryContent = ref("");
+const summaryLoading = ref(false);
+
+// 学习预期
+const expectationDialogVisible = ref(false);
+const expectationContent = ref("");
+const expectationSaved = ref("");
+const savingExpectation = ref(false);
 
 // 当前会话碎片列表
 interface FragmentItem {
@@ -209,8 +217,22 @@ const endTimer = async (content: string) => {
   }
 };
 
-const openSummaryDialog = () => {
+const openSummaryDialog = async () => {
   summaryDialogVisible.value = true;
+  // 有残片且未填写过总结时，用 AI 聚合草稿作为编辑起点
+  if (!summaryContent.value.trim() && fragmentsList.value.length > 0) {
+    summaryLoading.value = true;
+    try {
+      const res = await getReportDraft(taskInfo.value.sessionNum);
+      if (res?.code === 200 && res.data) {
+        summaryContent.value = res.data;
+      }
+    } catch {
+      // 草稿失败不阻塞手写
+    } finally {
+      summaryLoading.value = false;
+    }
+  }
 };
 
 const closeSummaryDialog = () => {
@@ -226,6 +248,7 @@ const loadTaskSession = async () => {
   try {
     const res = await startOrContinueStudySession(taskNum);
     Object.assign(taskInfo.value, res.data);
+    await loadExpectation();
     if (taskInfo.value.sessionState === "ONGOING") {
       startTimer();
     } else {
@@ -237,6 +260,41 @@ const loadTaskSession = async () => {
   }
 };
 
+// 学习预期：会话必须有预期才能开始计时
+const loadExpectation = async () => {
+  if (!taskInfo.value.sessionNum) return;
+  try {
+    const res = await getExpectation(taskInfo.value.sessionNum);
+    expectationSaved.value = res?.data?.description || "";
+  } catch {
+    expectationSaved.value = "";
+  }
+  if (!expectationSaved.value) {
+    expectationDialogVisible.value = true;
+  }
+};
+
+const saveExpectation = async () => {
+  if (!expectationContent.value.trim()) {
+    ElMessage.warning("学习预期不可为空");
+    return;
+  }
+  savingExpectation.value = true;
+  try {
+    const res = await upsertExpectation(taskInfo.value.sessionNum, expectationContent.value);
+    if (res?.code === 200) {
+      expectationSaved.value = expectationContent.value;
+      expectationDialogVisible.value = false;
+    } else {
+      ElMessage.error(res?.message || "保存失败");
+    }
+  } catch (e: any) {
+    ElMessage.error(e.message || "请求失败");
+  } finally {
+    savingExpectation.value = false;
+  }
+};
+
 const initPage = async () => {
   const hasPermission = await checkAudioPermission();
   if (!hasPermission) {
@@ -323,6 +381,19 @@ onUnmounted(() => {
       <span class="status-text">状态：{{ statusText }}</span>
     </div>
 
+    <!-- 学习预期 -->
+    <article class="surface-card expectation-card" v-if="expectationSaved">
+      <span class="expectation-label">本次预期</span>
+      <span class="expectation-text">{{ expectationSaved }}</span>
+      <el-button
+        text
+        size="small"
+        @click="expectationContent = expectationSaved; expectationDialogVisible = true"
+      >
+        修改
+      </el-button>
+    </article>
+
     <el-alert
       v-if="taskInfo.systemMessage"
       :title="taskInfo.systemMessage"
@@ -415,12 +486,38 @@ onUnmounted(() => {
     </template>
   </el-dialog>
 
-  <el-dialog v-model="summaryDialogVisible" title="结束会话总结" width="520px">
+  <el-dialog
+    v-model="expectationDialogVisible"
+    title="学习预期"
+    width="520px"
+    :close-on-click-modal="false"
+    :close-on-press-escape="false"
+    :show-close="!!expectationSaved"
+  >
+    <p class="dialog-hint">开始学习前，写下这次想学会什么。结束时会与实际学习内容对照。</p>
     <el-input
+      type="textarea"
+      v-model="expectationContent"
+      placeholder="例如：理解线程池的核心参数和拒绝策略"
+      :rows="4"
+    />
+    <template #footer>
+      <el-button v-if="expectationSaved" @click="expectationDialogVisible = false">取消</el-button>
+      <el-button type="success" :loading="savingExpectation" @click="saveExpectation">确定</el-button>
+    </template>
+  </el-dialog>
+
+  <el-dialog v-model="summaryDialogVisible" title="结束会话总结" width="560px">
+    <div v-if="expectationSaved" class="summary-expectation">
+      <span class="expectation-label">本次预期</span>
+      <span>{{ expectationSaved }}</span>
+    </div>
+    <el-input
+      v-loading="summaryLoading"
       type="textarea"
       v-model="summaryContent"
-      placeholder="请输入本次学习内容总结"
-      :rows="5"
+      placeholder="总结本次学到的内容（已有残片时自动生成草稿，可修改）"
+      :rows="8"
     />
     <template #footer>
       <el-button @click="closeSummaryDialog">取消</el-button>
@@ -443,6 +540,45 @@ onUnmounted(() => {
   gap: 12px;
 }
 
+.expectation-card {
+  display: flex;
+  align-items: center;
+  gap: 10px;
+  padding: 10px 16px;
+}
+
+.expectation-label {
+  flex-shrink: 0;
+  font-size: 12px;
+  font-weight: 700;
+  color: var(--green-700);
+  background: #e8f5e9;
+  padding: 2px 8px;
+  border-radius: 4px;
+}
+
+.expectation-text {
+  flex: 1;
+  font-size: 14px;
+  color: var(--text-primary);
+  word-break: break-word;
+}
+
+.dialog-hint {
+  margin: 0 0 10px;
+  font-size: 13px;
+  color: var(--text-secondary);
+}
+
+.summary-expectation {
+  display: flex;
+  align-items: flex-start;
+  gap: 8px;
+  margin-bottom: 10px;
+  font-size: 13px;
+  color: var(--text-secondary);
+}
+
 .status-text {
   font-size: 14px;
   color: var(--text-secondary);