fix: 修复学生代码窃取 token、提示词链 XSS 和打分没有上限的问题

- 运行提交代码的 iframe（编辑器预览、随机评分弹窗、/submission/:id、全屏预览）
  加上 sandbox，不给 allow-same-origin，代码读不到 localStorage 里的 token
- 提示词和 AI 回复的 markdown 渲染时转义原始 HTML，链接只放行 http(s)/mailto；
  ChainModal 也改用这个渲染函数
- 打分限定 1-5 分（超出返回 422），不能给自己的提交打分

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

client/src/components/ai/RandomRatingModal.vue

@@ -14,7 +14,11 @@
       {{ current.task_title }} · 提交者 {{ current.username }}
     </n-text>
     <div class="preview-wrapper">
-      <iframe class="preview-iframe" :srcdoc="previewContent"></iframe>
+      <iframe
+        class="preview-iframe"
+        :sandbox="PREVIEW_SANDBOX"
+        :srcdoc="previewContent"
+      ></iframe>
     </div>
     <div class="rate-row">
       <n-rate
@@ -38,7 +42,10 @@ import { ref, watch, onUnmounted } from "vue"
 import { useMessage } from "naive-ui"
 import { Submission } from "../../api"
 import { streaming } from "../../store/prompt"
-import { buildPreviewDocument } from "../../utils/previewDocument"
+import {
+  buildPreviewDocument,
+  PREVIEW_SANDBOX,
+} from "../../utils/previewDocument"
 import type { RandomRatingItem } from "../../utils/type"
 
 const message = useMessage()

client/src/components/editor/Preview.vue

@@ -42,7 +42,11 @@
     </n-flex>
   </n-flex>
   <div class="iframe-wrapper" :style="iframeWrapperStyle">
-    <iframe class="iframe" :srcdoc="previewContent"></iframe>
+    <iframe
+      class="iframe"
+      :sandbox="PREVIEW_SANDBOX"
+      :srcdoc="previewContent"
+    ></iframe>
   </div>
 </template>
 <script lang="ts" setup>
@@ -54,7 +58,10 @@ import { submission } from "../../store/submission"
 import { useMessage } from "naive-ui"
 import { Icon } from "@iconify/vue"
 import copy from "copy-text-to-clipboard"
-import { buildPreviewDocument } from "../../utils/previewDocument"
+import {
+  buildPreviewDocument,
+  PREVIEW_SANDBOX,
+} from "../../utils/previewDocument"
 
 interface Props {
   html: string
@@ -145,9 +152,14 @@ function open() {
   } else {
     const newTab = window.open("about:blank", "_blank")
     if (!newTab) return
-    newTab.document.open()
-    newTab.document.write(getContent())
-    newTab.document.close()
+    // 新标签页和本站同源，代码要放进带 sandbox 的 iframe 里跑
+    const doc = newTab.document
+    doc.open()
+    doc.write(
+      `<!DOCTYPE html><title>预览</title><style>html,body,iframe{margin:0;width:100%;height:100%;border:0;display:block}</style><iframe sandbox="${PREVIEW_SANDBOX}"></iframe>`,
+    )
+    doc.close()
+    doc.querySelector("iframe")!.srcdoc = getContent()
   }
 }
 

client/src/components/submissions/ChainModal.vue

@@ -240,7 +240,7 @@
 import { computed, ref, watch } from "vue"
 import { NPopconfirm, NButton, useMessage } from "naive-ui"
 import { Icon } from "@iconify/vue"
-import { marked } from "marked"
+import { renderMarkdown } from "../../utils/markdown"
 import { Prompt, Submission } from "../../api"
 import type { PromptRound } from "../../utils/type"
 import { user, roleSuper } from "../../store/user"
@@ -301,10 +301,6 @@ const selectedPageHtml = computed(() => {
   return `<!DOCTYPE html><html><head><meta charset="utf-8">${style}</head><body>${round.html}${script}</body></html>`
 })
 
-function renderMarkdown(text: string): string {
-  return marked.parse(text) as string
-}
-
 function isPromptLong(text: string): boolean {
   return text.length > 220 || text.split(/\r?\n/).length > 4
 }