feat: connect hybrid retrieval evidence

frontend/src/App.vue

@@ -1,7 +1,8 @@
 <script setup lang="ts">
 import { computed, onMounted, ref, watch } from 'vue'
 import { Activity, BookOpen, Bot, CheckCircle2, ChevronRight, Database, FileText, Globe2, Link2, MessageSquareText, Plus, Search, Send, ShieldCheck, Sparkles, AlertCircle } from 'lucide-vue-next'
-import { createKnowledge, createSource, getHealth, getKnowledge, getSources, retrieveKnowledge, type SourceItem } from './api'
+import { createKnowledge, createSource, getHealth, getKnowledge, getSources, type SourceItem } from './api'
+import { retrieveHybrid } from './services/hybrid'
 type Page='chat'|'knowledge'|'sources'|'evaluation'
 const page=ref<Page>('chat'), apiStatus=ref('检测中'), question=ref(''), busy=ref(false), search=ref(''), showForm=ref(false), error=ref(''), notice=ref('')
 const messages=ref([{role:'assistant',content:'你好！我是边疆红驿文旅问答原型。当前后端仅为基础接口，尚未接入知识检索和大语言模型。'}] as {role:string;content:string;sources?:{title:string;source_url?:string|null}[]}[])
@@ -15,7 +16,7 @@ async function saveSource(){error.value='';notice.value='';if(!sourceForm.value.
 let sourceSearchTimer:number|undefined
 watch(sourceSearch,()=>{window.clearTimeout(sourceSearchTimer);sourceSearchTimer=window.setTimeout(refreshSources,260)})
 onMounted(async()=>{try{await getHealth();apiStatus.value='已连接'}catch{apiStatus.value='未连接'}await Promise.all([refresh(),refreshSources()])})
-async function send(){const q=question.value.trim();if(!q||busy.value)return;messages.value.push({role:'user',content:q});question.value='';busy.value=true;try{const r=await retrieveKnowledge({query:q,top_k:5});const content=r.status==='no_evidence'?'未检索到可用的已核验知识依据。请调整问题或补充审核后的资料。':`已检索到 ${r.total_hits} 条已核验依据（${r.elapsed_ms.toFixed(1)} ms）。当前仅展示检索证据，尚未接入大语言模型生成回答。`;messages.value.push({role:'assistant',content,sources:r.results.map(hit=>({title:`${hit.title}：${hit.snippet}`,source_url:hit.source_url}))})}catch(e){messages.value.push({role:'assistant',content:e instanceof Error?e.message:'暂时无法连接检索服务。'})}finally{busy.value=false}}
+async function send(){const q=question.value.trim();if(!q||busy.value)return;messages.value.push({role:'user',content:q});question.value='';busy.value=true;try{const r=await retrieveHybrid({query:q,top_k:5,candidate_k:50});const content=r.status==='no_evidence'?'未检索到可用的已核验知识依据。请调整问题或补充审核后的资料。':`已通过 RRF 混合检索命中 ${r.total_hits} 条依据（关键词 ${r.lexical_total_hits}，向量 ${r.vector_total_hits}，${r.elapsed_ms.toFixed(1)} ms）。当前仅展示检索证据，尚未接入大语言模型生成回答。`;messages.value.push({role:'assistant',content,sources:r.results.map(hit=>({title:`${hit.title}：${hit.snippet}`,source_url:hit.source_url}))})}catch(e){messages.value.push({role:'assistant',content:e instanceof Error?e.message:'暂时无法连接混合检索服务。'})}finally{busy.value=false}}
 function validUrl(value:string){try{if(value)new URL(value);return true}catch{return false}}
 async function save(){error.value='';notice.value='';if(!form.value.title.trim()||!form.value.content.trim()){error.value='请填写知识标题和正文。';return}if(!validUrl(form.value.source_url)){error.value='来源网址必须是有效的 http(s) 地址。';return}try{await createKnowledge({...form.value,title:form.value.title.trim(),content:form.value.content.trim(),...(form.value.source_url?{source_url:form.value.source_url}:{})});form.value={title:'',category:'旅游资源',content:'',source_url:''};showForm.value=false;notice.value='已保存为待审核条目，尚未进入检索索引。';await refresh()}catch(e){error.value=e instanceof Error?e.message:'保存失败'}}
 </script>