feat: StartTask 页面学习材料展示与编辑

- 新增学习材料卡片区域，支持 Markdown 渲染展示
- 支持弹窗编辑材料内容，保存到后端 task.materialUrl
- taskInfo 新增 taskId 和 materialUrl 字段
- materialHtml computed 自动将链接渲染为可点击标签
- 卡片样式与页面风格统一（绿色主题）

src/components/StartTask.vue

@@ -2,6 +2,7 @@
 import { computed, onMounted, onUnmounted, ref, watch } from "vue";
 import { useRoute } from "vue-router";
 import { ElMessage, ElMessageBox } from "element-plus";
+import request from "@/utils/request";
 import { useTimer } from "@/components/composables/useTimer";
 import {
   continueSession,
@@ -133,6 +134,8 @@ const taskInfo = ref({
   sessionState: "--",
   taskName: "",
   taskNum,
+  taskId: 0,
+  materialUrl: "",
   startTime: "",
   endTime: "",
   lastStartTime: "",
@@ -143,6 +146,65 @@ const taskInfo = ref({
   systemMessage: "",
 });
 
+// 学习材料展示/编辑
+const editingMaterial = ref(false);
+const editMaterialContent = ref("");
+const savingMaterial = ref(false);
+const materialHtml = computed(() => {
+  const raw = taskInfo.value.materialUrl || "";
+  if (!raw.trim()) return "";
+  let html = raw;
+  const links: string[] = [];
+  html = html.replace(/\[([^\]]+)\]\(([^)]+)\)/g, (_m: string, text: string, url: string) => {
+    const tag = `<a href="${url.replace(/"/g, "&quot;")}" target="_blank" rel="noopener">${text}</a>`;
+    links.push(tag);
+    return `__LINK_${links.length - 1}__`;
+  });
+  html = html.replace(/https?:\/\/[^\s)\u3001\uFF09\u300D\u300B<>]+/g, (url) => {
+    const clean = url.replace(/[.。,，;；!！?？）】」』\]]+$/, "");
+    const tag = `<a href="${clean.replace(/"/g, "&quot;")}" target="_blank" rel="noopener">${clean}</a>`;
+    links.push(tag);
+    return `__LINK_${links.length - 1}__`;
+  });
+  html = html.replace(/\n/g, "<br>");
+  for (let i = 0; i < links.length; i++) {
+    html = html.replace(`__LINK_${i}__`, links[i]);
+  }
+  return html;
+});
+
+function startEditMaterial() {
+  editMaterialContent.value = taskInfo.value.materialUrl;
+  editingMaterial.value = true;
+}
+
+async function saveMaterial() {
+  savingMaterial.value = true;
+  try {
+    // 先拉取完整任务数据，只改 materialUrl，其他字段保持不变
+    const res = await request.get(`/tasks/${taskInfo.value.taskId}`);
+    const current = res?.data || {};
+    await request.put(`/tasks/${taskInfo.value.taskId}`, {
+      id: taskInfo.value.taskId,
+      taskName: current.taskName,
+      taskDescription: current.taskDescription || "",
+      materialUrl: editMaterialContent.value,
+      urgency: current.urgency ?? 0,
+      importance: current.importance ?? 0,
+      contentDifficulty: current.contentDifficulty ?? 0,
+      futureValue: current.futureValue ?? 0,
+      subjectivePriority: current.subjectivePriority ?? 0,
+    });
+    taskInfo.value.materialUrl = editMaterialContent.value;
+    editingMaterial.value = false;
+    ElMessage.success("学习材料已更新");
+  } catch (e: any) {
+    ElMessage.error(e?.message || "更新失败");
+  } finally {
+    savingMaterial.value = false;
+  }
+}
+
 const {
   timerMinutes,
   timerSeconds,
@@ -550,6 +612,30 @@ onUnmounted(() => {
       <span class="status-text">状态：{{ statusText }}</span>
     </div>
 
+    <!-- 学习材料 -->
+    <article class="surface-card material-session-card">
+      <div class="material-session-header">
+        <span class="material-session-label">学习材料</span>
+        <el-button
+          v-if="!editingMaterial"
+          text
+          size="small"
+          type="primary"
+          @click="startEditMaterial"
+        >编辑</el-button>
+      </div>
+      <div v-if="materialHtml" class="material-session-content" v-html="materialHtml" />
+      <p v-else class="empty-text">暂未填写材料地址</p>
+      <el-dialog v-model="editingMaterial" title="编辑学习材料" width="560px">
+        <el-input v-model="editMaterialContent" type="textarea" :rows="10" placeholder="支持 Markdown 格式" />
+        <p class="edit-hint">[链接文字](url) 或直接粘贴链接，保存时自动获取标题</p>
+        <template #footer>
+          <el-button @click="editingMaterial = false">取消</el-button>
+          <el-button type="success" :loading="savingMaterial" @click="saveMaterial">保存</el-button>
+        </template>
+      </el-dialog>
+    </article>
+
     <!-- 学习预期 -->
     <article class="surface-card expectation-card" v-if="expectationSaved">
       <span class="expectation-label">本次预期</span>
@@ -804,6 +890,50 @@ onUnmounted(() => {
   word-break: break-word;
 }
 
+.material-session-card {
+  padding: 12px 16px;
+}
+
+.material-session-header {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  margin-bottom: 6px;
+}
+
+.material-session-label {
+  font-size: 12px;
+  font-weight: 700;
+  color: var(--green-700);
+  background: #e8f5e9;
+  padding: 2px 8px;
+  border-radius: 4px;
+}
+
+.material-session-content {
+  font-size: 14px;
+  line-height: 1.7;
+  word-break: break-word;
+  color: var(--text-primary);
+}
+
+.material-session-content :deep(a) {
+  color: var(--green-600);
+  text-decoration: none;
+  border-bottom: 1px dashed var(--green-400);
+}
+
+.material-session-content :deep(a:hover) {
+  color: var(--green-800);
+  border-bottom-style: solid;
+}
+
+.edit-hint {
+  margin: 6px 0 0;
+  font-size: 12px;
+  color: var(--text-secondary);
+}
+
 .dialog-hint {
   margin: 0 0 10px;
   font-size: 13px;