feat(agent): stream admin debug preview

ai_knowledge_base_v2/apps/admin-web/src/components/StreamingMarkdownMessage.vue

@@ -0,0 +1,53 @@
+<script setup lang="ts">
+import MarkdownIt from "markdown-it";
+import { computed } from "vue";
+
+const props = defineProps<{
+  content: string;
+  streaming?: boolean;
+}>();
+
+const markdown = new MarkdownIt({ breaks: true, html: false, linkify: true });
+const answer = computed(() => stripStreamingReasoning(props.content).replace(/^\s+/, ""));
+const renderedContent = computed(() => answer.value.trim() ? markdown.render(answer.value) : "");
+
+function stripStreamingReasoning(content: string) {
+  const lower = content.toLowerCase();
+  let visible = "";
+  let cursor = 0;
+  let reasoningDepth = 0;
+  while (cursor < content.length) {
+    const tagStart = content.indexOf("<", cursor);
+    if (tagStart === -1) {
+      if (reasoningDepth === 0) visible += content.slice(cursor);
+      break;
+    }
+    if (reasoningDepth === 0) visible += content.slice(cursor, tagStart);
+    const tail = lower.slice(tagStart);
+    const openTag = tail.match(/^<think(?:\s[^>]*)?>/);
+    if (openTag) {
+      reasoningDepth += 1;
+      cursor = tagStart + openTag[0].length;
+      continue;
+    }
+    const closeTag = tail.match(/^<\/think\s*>/);
+    if (closeTag) {
+      reasoningDepth = Math.max(0, reasoningDepth - 1);
+      cursor = tagStart + closeTag[0].length;
+      continue;
+    }
+    if ("<think".startsWith(tail) || "</think>".startsWith(tail)) break;
+    if (reasoningDepth === 0) visible += "<";
+    cursor = tagStart + 1;
+  }
+  return visible;
+}
+</script>
+
+<template>
+  <div v-if="renderedContent" class="agent-preview-markdown" v-html="renderedContent"></div>
+  <div v-else-if="streaming" class="agent-preview-generation-state">
+    <span></span><span></span><span></span>
+    思考中
+  </div>
+</template>