chore: initialize fullstack starter and team guidelines

frontend/src/api.ts

@@ -0,0 +1,4 @@
+export async function getHealth(){const r=await fetch('/api/health');if(!r.ok)throw new Error('health failed');return r.json()}
+export async function askQuestion(question:string){const r=await fetch('/api/chat',{method:'POST',headers:{'Content-Type':'application/json'},body:JSON.stringify({question})});if(!r.ok)throw new Error('chat failed');return r.json() as Promise<{answer:string;status:string;sources:{title:string;source_url?:string|null}[]}>}
+export async function getKnowledge(){const r=await fetch('/api/knowledge');if(!r.ok)throw new Error('knowledge failed');return r.json() as Promise<any[]>}
+export async function createKnowledge(payload:{title:string;category:string;content:string;source_url?:string}){const r=await fetch('/api/knowledge',{method:'POST',headers:{'Content-Type':'application/json'},body:JSON.stringify(payload)});if(!r.ok)throw new Error('保存失败，请检查网址格式及后端状态');return r.json()}