Knowledge Chat: surface LangSmith trace link when tracing enabled (reads /rag/config)

ui/src/components/features/KnowledgeChatView.tsx

@@ -40,6 +40,7 @@ export function KnowledgeChatView({ onGpuActivity }: Props = {}) {
   const [catalogDocs, setCatalogDocs] = useState<number | null>(null)
   const [showArch, setShowArch] = useState(true)
   const [activeStage, setActiveStage] = useState<number | null>(null)
+  const [traceCfg, setTraceCfg] = useState<{ tracing: boolean; project: string; smith_url: string } | null>(null)
   const bottomRef = useRef<HTMLDivElement>(null)
 
   const loadMeta = useCallback(async () => {
@@ -77,6 +78,13 @@ export function KnowledgeChatView({ onGpuActivity }: Props = {}) {
     loadCatalog()
   }, [loadMeta, loadCatalog])
 
+  useEffect(() => {
+    fetch('/rag/config')
+      .then((r) => (r.ok ? r.json() : null))
+      .then((c) => { if (c) setTraceCfg(c) })
+      .catch(() => {})
+  }, [])
+
   useEffect(() => {
     bottomRef.current?.scrollIntoView({ behavior: 'smooth' })
   }, [messages, loading])
@@ -351,6 +359,17 @@ export function KnowledgeChatView({ onGpuActivity }: Props = {}) {
                 <StatusPill ok={health.llm} label="LLM" />
               </>
             )}
+            {traceCfg?.tracing && (
+              <a
+                href={traceCfg.smith_url}
+                target="_blank"
+                rel="noreferrer"
+                title={`LangSmith project: ${traceCfg.project}`}
+                className="inline-flex items-center gap-1 rounded border border-emerald-400/50 bg-emerald-500/15 px-2 py-1 text-[10px] font-medium text-emerald-300 hover:bg-emerald-500/25"
+              >
+                <Workflow className="h-3.5 w-3.5" /> LangSmith ↗
+              </a>
+            )}
             <button
               type="button"
               onClick={() => setShowArch((v) => !v)}
@@ -369,7 +388,7 @@ export function KnowledgeChatView({ onGpuActivity }: Props = {}) {
 
       {showArch && (
         <div className="shrink-0 border-b border-border bg-surface-overlay/20 px-4 py-3">
-          <RagFlow loading={loading} ingesting={ingesting} activeStage={activeStage} />
+          <RagFlow loading={loading} ingesting={ingesting} activeStage={activeStage} smithUrl={traceCfg?.tracing ? traceCfg.smith_url : null} project={traceCfg?.project} />
         </div>
       )}
 
@@ -565,7 +584,7 @@ const QUERY_STAGES = [
 
 const STAGE_LABEL = ['Question', 'Embed', 'Retrieve', 'Context', 'LLM', 'Answer']
 
-function RagFlow({ loading, ingesting, activeStage }: { loading: boolean; ingesting: boolean; activeStage: number | null }) {
+function RagFlow({ loading, ingesting, activeStage, smithUrl, project }: { loading: boolean; ingesting: boolean; activeStage: number | null; smithUrl?: string | null; project?: string }) {
   return (
     <div className="space-y-2">
       <div className="flex flex-wrap items-center gap-2 text-[9px] font-semibold uppercase tracking-wider text-foreground-faint">
@@ -574,6 +593,9 @@ function RagFlow({ loading, ingesting, activeStage }: { loading: boolean; ingest
           <span className="h-1.5 w-1.5 rounded-full bg-emerald-400" /> orchestrated by LangChain
         </span>
         <span className="rounded bg-docker/15 px-1.5 py-0.5 font-mono text-[8px] normal-case text-docker">ChromaDB · Docling · sentence-transformers</span>
+        {smithUrl && (
+          <a href={smithUrl} target="_blank" rel="noreferrer" title={project ? `LangSmith project: ${project}` : 'LangSmith'} className="inline-flex items-center gap-1 rounded-md border border-emerald-400/40 bg-emerald-500/10 px-1.5 py-0.5 font-mono text-[8px] normal-case text-emerald-300 hover:bg-emerald-500/20">LangSmith traces ↗</a>
+        )}
         {activeStage != null && (
           <span className="ml-auto flex items-center gap-1 normal-case text-docker">
             <span className="h-1.5 w-1.5 animate-ping rounded-full bg-docker" /> {STAGE_LABEL[activeStage] || 'working'}…