圆桌会商各步接入流式回答速度指示器，复用主聊天 SpeedPill 与全局开关。

新增 DialogueSpeedMeter 与 useDialogueSpeedMetrics，在 Step1/2/3 气泡底部展示 tok/s 与耗时。

Co-authored-by: Cursor <cursoragent@cursor.com>

frontend-web/src/roundtable-planning/components/Step3ReportMode.tsx

@@ -30,6 +30,7 @@ import {
 } from "lucide-react";
 
 import { useArtifacts } from "@/components/workspace/artifacts";
+import { useLocalSettings } from "@/core/settings";
 import { cn } from "@/lib/utils";
 import {
   buildArtifactDownloadUrl,
@@ -45,6 +46,7 @@ import { Step2SandboxLayout } from "@/roundtable-planning/components/Step2Sandbo
 import { markdownComponents } from "@/roundtable-planning/components/markdown-components";
 import type { DraftStep3Snapshot } from "@/roundtable-planning/api/drafts";
 import { useAutoScroll } from "@/roundtable-planning/hooks/useAutoScroll";
+import { useDialogueSpeedMetrics } from "@/roundtable-planning/hooks/useDialogueSpeedMetrics";
 import {
   useStep3Report,
   type ReportIntent,
@@ -480,6 +482,10 @@ function AgentProgressPanel({
   const inputLocked = phase === "creating";
   const scrollRef = useRef<HTMLDivElement>(null);
   const { atBottom, scrollToBottom } = useAutoScroll(scrollRef, [dialogues]);
+  // 「回答速度指示器」—— 与主页面共用全局开关 streamSpeedMeterEnabled。
+  const [localSettings] = useLocalSettings();
+  const speedMeterEnabled = localSettings.display.streamSpeedMeterEnabled;
+  const dialogueMetrics = useDialogueSpeedMetrics(dialogues);
   const [revisionText, setRevisionText] = useState("");
 
   const handleRevisionSubmit = (e: FormEvent<HTMLFormElement>) => {
@@ -548,6 +554,7 @@ function AgentProgressPanel({
             <Step2Message
               key={msg.id}
               msg={msg}
+              metric={speedMeterEnabled ? dialogueMetrics.get(msg.id) : undefined}
               onArtifactStepClick={(step) => onArtifactStepClick(msg, step)}
               onFileCardClick={(path) => {
                 if (msg.agentThreadId) onArtifactPreview(msg.agentThreadId, path);