技能展示适配持久化 + 参考文献收集与新对话流式修复

- 后端新增 skill_display_adapters 表，持久化每个技能的 display 配置与 sample
  payload；/api/skills 列表、详情、设置接口同步读写
- 新增 /api/skills/{name}/display-sample 端点，编辑器优先加载库中样例
- 前端展示适配面板改为从后端加载持久样例，无样例时提示"自动识别"
- 参考文献收集修复：仅在 bash/shell/python 等执行类工具上从参数推断技能
  名，避免 read_file / web_fetch 误匹配；引用列表纳入最新一条助手消息
- ChatBox 改用「最新 human → 最新 ai」窗口收集引用，并仅保留 citation
  模式
- 修复「新对话」点击后已发消息消失：useThreadStream 只在 threadId 切回
  空值时重置/中止 SSE，避免 onCreated 分配 id 时把刚开始的流打断；
  ChatPage 在 landing 状态隐藏 MessageList，移除 KeyedChatPage remount
- 技能详情对话框：所有者可查看源码与文件 tab（不再要求管理员）
- LocalSandbox：Windows PowerShell 5 路径下把 && 重写为 ;，并以
  UTF-8 解码 subprocess 输出，避免中文乱码
- knowledge-search-v2 mock 样例改为中文固定测试数据

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

frontend-web/src/pages/ChatPage.tsx

@@ -231,14 +231,25 @@ export default function ChatPage() {
           </header>
           <main className="flex min-h-0 max-w-full grow flex-col">
             <div className="flex size-full justify-center">
-              <MessageList
-                className={cn("size-full", !isLandingState && "pt-10")}
-                threadId={threadId}
-                thread={thread}
-                paddingBottom={messageListPaddingBottom}
-                tokenUsageEnabled={tokenUsageEnabled}
-                onClarificationSubmit={handleClarificationSubmit}
-              />
+              {/*
+                Landing state covers two cases: (a) a brand-new chat that
+                hasn't sent anything yet, and (b) the user clicking 「新对话」
+                mid-stream. In (b) the underlying useStream's internal
+                stream.values takes one or two effect ticks to clear, so
+                rendering MessageList unconditionally would leak the previous
+                conversation under the welcome card. Skip rendering during
+                the landing state to guarantee a clean slate.
+              */}
+              {!isLandingState && (
+                <MessageList
+                  className={cn("size-full", "pt-10")}
+                  threadId={threadId}
+                  thread={thread}
+                  paddingBottom={messageListPaddingBottom}
+                  tokenUsageEnabled={tokenUsageEnabled}
+                  onClarificationSubmit={handleClarificationSubmit}
+                />
+              )}
             </div>
             <div className="absolute right-0 bottom-0 left-0 z-30 flex justify-center px-4">
               <div

frontend-web/src/pages/WorkspaceRoutes.tsx

@@ -1,5 +1,5 @@
 import type { CSSProperties, ReactNode } from "react";
-import { Navigate, Route, Routes, useLocation } from "react-router-dom";
+import { Navigate, Route, Routes } from "react-router-dom";
 
 import { getStoredAuth } from "@/core/auth";
 
@@ -89,20 +89,6 @@ export function ChatRuntime({ children }: { children: ReactNode }) {
   );
 }
 
-/**
- * 让 ChatPage 在每次真正的 react-router navigation 上完整 remount。
- *
- * 背景:点「新对话」时即使路径不变,我们也会用 `navigate(..., { replace: true,
- * state: { resetAt } })` 强制刷新 location.key —— 用它作 key 能保证 useStream、
- * useThreadStream、optimistic state、refs 一次性全部丢弃,避免上一条流的
- * `stream.values` 残留把欢迎页底下的旧消息拖出来(SDK 的 stream.clear() 需要
- * 多次 effect tick 才会清干净,中间过渡帧用户能看见)。
- */
-function KeyedChatPage({ render }: { render: () => ReactNode }) {
-  const key = useLocation().key;
-  return <ChatRuntime key={key}>{render()}</ChatRuntime>;
-}
-
 export default function WorkspaceRoutes({
   pageSidebarCollapsed = false,
   pageSidebarHidden = false,
@@ -137,7 +123,9 @@ export default function WorkspaceRoutes({
         path="chats/:thread_id"
         element={
           <WorkspaceLayout {...layoutProps}>
-            <KeyedChatPage render={() => <ChatPage />} />
+            <ChatRuntime>
+              <ChatPage />
+            </ChatRuntime>
           </WorkspaceLayout>
         }
       />