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/hooks/use-consultation-run.ts

@@ -734,6 +734,7 @@ export function useConsultationRun(params: ConsultationRunParams) {
       setConsultationPhase("streaming");
     }
     setStreamingReply({ sessionId, text: "", timeline: [] });
+    let responseKind: "smalltalk" | undefined;
     let latestPartialReply = "";
     let thinkingSections: PublicThinkingSection[] = [];
     let streamedThinking = "";
@@ -751,6 +752,7 @@ export function useConsultationRun(params: ConsultationRunParams) {
         setStreamingReply({
           sessionId,
           text: partialReply,
+          responseKind,
           thinkingText: frame.thinking.trim() || undefined,
           thinkingSections: thinkingSections.length ? thinkingSections : undefined,
           timeline: timelineState.rows,
@@ -807,6 +809,7 @@ export function useConsultationRun(params: ConsultationRunParams) {
       if (!response.body) {
         throw new ConsultationResponseError(502, "浏览器未收到可读取的回答流");
       }
+      responseKind = response.headers.get("x-jyotish-response-kind") === "smalltalk" ? "smalltalk" : undefined;
       let techniqueTruth = response.headers.get("x-jyotish-technique-truth") ?? "unknown";
       let workflowReceipt: AgentExecutionReceipt["workflow"] = {
         route: response.headers.get("x-jyotish-workflow-route") ?? "unknown",
@@ -859,7 +862,7 @@ export function useConsultationRun(params: ConsultationRunParams) {
 
       if ((response.headers.get("content-type") ?? "").includes("application/x-ndjson")) {
         const parser = createNdjsonParser((event) => {
-          timelineState = reduceConsultationTimeline(timelineState, event);
+          if (responseKind !== "smalltalk") timelineState = reduceConsultationTimeline(timelineState, event);
           frames.touch();
           if (event.type === "answer.delta") {
             answer += event.text;
@@ -892,9 +895,13 @@ export function useConsultationRun(params: ConsultationRunParams) {
           }
           if (event.type === "run.completed") {
             runCompleted = true;
-            agentExecutionReceipt = event.receipt;
-            workflowReceipt = event.receipt.workflow;
-            techniqueTruth = event.receipt.techniqueTruth ?? "unknown";
+            if (event.responseKind === "smalltalk") {
+              responseKind = "smalltalk";
+            } else if (event.receipt) {
+              agentExecutionReceipt = event.receipt;
+              workflowReceipt = event.receipt.workflow;
+              techniqueTruth = event.receipt.techniqueTruth ?? "unknown";
+            }
           }
           if (event.type === "run.failed") {
             if (event.code === "answer_truncated") {
@@ -908,7 +915,7 @@ export function useConsultationRun(params: ConsultationRunParams) {
             }
             throw new ConsultationResponseError(502, event.message);
           }
-          updateActivity(event);
+          if (responseKind !== "smalltalk") updateActivity(event);
         });
         while (true) {
           const { done, value } = await reader.read();
@@ -983,11 +990,13 @@ export function useConsultationRun(params: ConsultationRunParams) {
         messages: [...userSession.messages, {
           role: "assistant",
           text: reply.text,
-          ...(streamedThinking.trim() ? { thinkingText: streamedThinking.trim().slice(0, 4000) } : {}),
-          ...(thinkingSections.length ? { thinkingSections } : {}),
-          techniqueTruth,
-          workflowReceipt,
-          agentExecutionReceipt,
+          ...(responseKind === "smalltalk" ? { responseKind } : {
+            ...(streamedThinking.trim() ? { thinkingText: streamedThinking.trim().slice(0, 4000) } : {}),
+            ...(thinkingSections.length ? { thinkingSections } : {}),
+            techniqueTruth,
+            workflowReceipt,
+            agentExecutionReceipt,
+          }),
         }],
         updatedAt: timestamp(),
       };