feat(frontend): 上线报告协作与多轮 RAG 消息聚合体验

功能说明：\n- 新增报告协作页（Report Collaboration）核心状态层、消息适配与会话面板，支持按节点/阶段选择和协作上下文展示\n- 补齐 report-collaboration API 与类型定义，并接入页面路由/构建路径，形成可运行的协作链路\n- 重构多轮 RAG 与 write/artefact 消息分组逻辑，优化 AgentChat 与 DeepResearch 场景下的消息展示顺序与可读性\n- 新增/更新 DeepResearch 前端页面（Workbench、报告配置、沙箱联动）以承接报告生成与复用能力\n- 增加报表协作相关单测，覆盖事件归并、消息适配与关键 reducer 行为

frontend-web/src/components/landing/hero.tsx

@@ -3,6 +3,7 @@
 import { ChevronRightIcon } from "lucide-react";
 import Link from "next/link";
 
+import deerMaskUrl from "@/assets/deer.svg";
 import { Button } from "@/components/ui/button";
 import { FlickeringGrid } from "@/components/ui/flickering-grid";
 import Galaxy from "@/components/ui/galaxy";
@@ -29,7 +30,11 @@ export function Hero({ className }: { className?: string }) {
         />
       </div>
       <FlickeringGrid
-        className="absolute inset-0 z-0 translate-y-8 mask-[url(/images/deer.svg)] mask-size-[100vw] mask-center mask-no-repeat md:mask-size-[72vh]"
+        className="absolute inset-0 z-0 translate-y-8 mask-size-[100vw] mask-center mask-no-repeat md:mask-size-[72vh]"
+        style={{
+          WebkitMaskImage: `url("${deerMaskUrl}")`,
+          maskImage: `url("${deerMaskUrl}")`,
+        }}
         squareSize={4}
         gridGap={4}
         color={"white"}

frontend-web/src/components/workspace/messages/multi-round-rag-message-list.tsx

@@ -6,7 +6,7 @@ import {
   SearchIcon,
   SparklesIcon,
 } from "lucide-react";
-import { useEffect, useState } from "react";
+import { useState } from "react";
 
 import {
   Conversation,
@@ -165,9 +165,6 @@ function MultiRoundRagTraceView({
   onSelectRetrieval: (item: MultiRoundRagRetrieval) => void;
 }) {
   const [open, setOpen] = useState(!trace.thinkingComplete);
-  useEffect(() => {
-    setOpen(!trace.thinkingComplete);
-  }, [trace.thinkingComplete]);
 
   return (
     <Collapsible
@@ -208,6 +205,7 @@ function MultiRoundRagTraceView({
               index={index + 1}
               round={round}
               isLoading={isLoading}
+              isActiveRound={isLoading && index === trace.rounds.length - 1}
               rehypePlugins={rehypePlugins}
               onSelectRetrieval={onSelectRetrieval}
             />
@@ -222,20 +220,22 @@ function MultiRoundRagRoundCard({
   index,
   round,
   isLoading,
+  isActiveRound,
   rehypePlugins,
   onSelectRetrieval,
 }: {
   index: number;
   round: MultiRoundRagRound;
   isLoading: boolean;
+  isActiveRound: boolean;
   rehypePlugins: MessageResponseProps["rehypePlugins"];
   onSelectRetrieval: (item: MultiRoundRagRetrieval) => void;
 }) {
-  const searching = Boolean(round.queryLoading);
+  const query = round.query.trim();
+  const searching = Boolean(query && round.queryLoading);
+  const showQuery = Boolean(query);
+  const showRetrievals = showQuery || round.retrievals.length > 0;
   const [open, setOpen] = useState(true);
-  useEffect(() => {
-    setOpen(searching || !round.query);
-  }, [round.id, round.query, searching]);
 
   return (
     <Collapsible open={open} onOpenChange={setOpen}>
@@ -254,7 +254,7 @@ function MultiRoundRagRoundCard({
                 <Loader2Icon className="size-3 animate-spin" />
                 检索中
               </span>
-            ) : (
+            ) : isActiveRound ? null : (
               <span className="text-muted-foreground text-[11px]">已完成</span>
             )}
             <ChevronDownIcon
@@ -277,7 +277,7 @@ function MultiRoundRagRoundCard({
             />
           </section>
         )}
-        {round.queryShow && (round.query || searching) && (
+        {showQuery && (
           <div
             className="border-primary/20 bg-primary/5 text-primary inline-flex max-w-full items-center gap-2 rounded-full border px-3 py-1.5"
             aria-live={searching ? "polite" : undefined}
@@ -291,11 +291,11 @@ function MultiRoundRagRoundCard({
               {round.queryTitle || "检索词"}
             </span>
             <span className="min-w-0 truncate text-xs font-medium">
-              {round.query || "正在生成检索词…"}
+              {query}
             </span>
           </div>
         )}
-        {round.queryShow && (
+        {showRetrievals && (
           <section>
             <div className="mb-2 flex items-center gap-2 text-sm font-medium">
               <FileTextIcon className="text-muted-foreground size-4" />