feat: add strict workflow taxonomy and claim badges

frontend/src/components/chat-message-row.tsx

@@ -1,4 +1,5 @@
 import { ChatMessageContent } from "@/components/chat-message-content";
+import { ClaimBoundaryBadge } from "@/components/claim-boundary-badge";
 import type { ChatMessageView } from "@/lib/chat-message-view";
 
 export function AgentAvatar() {
@@ -23,7 +24,7 @@ export function ChatMessageRow({ message }: { readonly message: ChatMessageView
           {message.role === "assistant" ? (
             message.state === "thinking"
               ? <div className="thinking"><i /><i /><i /></div>
-              : <ChatMessageContent text={message.text} />
+              : <><ClaimBoundaryBadge status={message.techniqueTruth} /><ChatMessageContent text={message.text} /></>
           ) : <p>{message.text}</p>}
         </div>
       </div>

frontend/src/components/claim-boundary-badge.tsx

@@ -0,0 +1,13 @@
+const boundaryCopy: Record<string, string> = {
+  unknown: "证据边界未知",
+  partial: "部分证据闭环",
+  observation_only: "仅观察",
+  blocked: "证据阻塞",
+  reference_only: "仅参考",
+};
+
+export function ClaimBoundaryBadge({ status }: { readonly status?: string }) {
+  const normalized = status?.trim() || "unknown";
+  const label = boundaryCopy[normalized] ?? `证据状态：${normalized}`;
+  return <p className="claim-boundary-badge">{label} · 不把未闭环内容包装成确定预测。</p>;
+}