feat(consult): add free model-classified smalltalk fast path

Keep full consultation tool contracts unchanged. Persist short replies and refund the original reservation atomically while recording actual model usage. Verify Linux frontend 3566/3566, database 40/40, Static home and gzip +0.0493%.

Co-Authored-By: Claude Code <noreply@anthropic.com>

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

@@ -53,7 +53,11 @@ export const ChatMessageRow = memo(function ChatMessageRow({
   stoppedNotice?: string;
 }>) {
   const messageRow = useRef<HTMLElement>(null);
-  const assistantLabel = message.state === "thinking"
+  const smalltalk = message.responseKind === "smalltalk";
+  const awaitingClassification = message.state === "thinking" && !message.text && !message.activity
+    && !message.thinkingText && message.timeline?.length === 0;
+  const quiet = smalltalk || awaitingClassification;
+  const assistantLabel = quiet ? "Jyotisha" : message.state === "thinking"
     ? "Jyotisha 正在分析"
     : message.state === "streaming"
       ? "Jyotisha 正在回答"
@@ -69,11 +73,11 @@ export const ChatMessageRow = memo(function ChatMessageRow({
   const activityLabel = message.activity?.label
     ?? (message.state === "thinking" ? "正在处理…" : undefined);
   const hasAnswer = Boolean(message.text.trim());
-  const consultTimeline = message.timeline;
+  const consultTimeline = quiet ? undefined : message.timeline;
   // Rows with a step timeline (every consultation and rectification reply) render
   // `ConsultationRunTimeline`; the activity panel is the fallback for rows without one.
-  const showLiveActivity = showActivity && consultTimeline === undefined;
-  const showThinkingPanel = showLiveActivity || (consultTimeline === undefined && Boolean(message.thinkingText?.trim()));
+  const showLiveActivity = !quiet && showActivity && consultTimeline === undefined;
+  const showThinkingPanel = !quiet && (showLiveActivity || (consultTimeline === undefined && Boolean(message.thinkingText?.trim())));
   const showSpokenAnswer = Boolean(message.text);
   const stackedThinkingAndAnswer = showThinkingPanel && showSpokenAnswer;
 
@@ -119,7 +123,7 @@ export const ChatMessageRow = memo(function ChatMessageRow({
     ? (
       <ChatMessageContent
         text={message.text}
-        auditRows={message.agentExecutionReceipt?.techniqueAuditTable}
+        auditRows={smalltalk ? undefined : message.agentExecutionReceipt?.techniqueAuditTable}
         streaming={message.state !== "settled"}
       />
     )

frontend/src/components/chat-transcript.tsx

@@ -42,6 +42,7 @@ export type ChatTranscriptProps = Readonly<{
   streamingThinking?: string;
   streamingSections?: readonly PublicThinkingSection[];
   streamingTimeline?: readonly ConsultationTimelineRow[];
+  streamingResponseKind?: "smalltalk";
   sessionId: string;
   sessionType: "consultation" | "birth_time_rectification";
   theme?: ConsultationDomain;
@@ -197,6 +198,7 @@ export const ChatTranscript = memo(function ChatTranscript({
   streamingThinking,
   streamingSections,
   streamingTimeline,
+  streamingResponseKind,
   sessionId,
   sessionType,
   theme,
@@ -214,6 +216,7 @@ export const ChatTranscript = memo(function ChatTranscript({
     streamingThinking,
     streamingSections,
     streamingTimeline,
+    streamingResponseKind,
   );
 
   return (
@@ -260,6 +263,7 @@ export function UnsplitChatTranscript({
   streamingThinking,
   streamingSections,
   streamingTimeline,
+  streamingResponseKind,
   sessionId,
   sessionType,
   theme,
@@ -278,6 +282,7 @@ export function UnsplitChatTranscript({
     streamingThinking,
     streamingSections,
     streamingTimeline,
+    streamingResponseKind,
   );
   return (
     <>