refactor(client): remove desktop sidebar collapse (NavToggle) — always docked

Drop the NavToggle collapse handle from both the chat Nav and the knowledge-space sidebar on desktop: the sidebar is always docked/visible and the related hover/ResizeObserver/measure state is removed. Mobile keeps the toggleable overlay drawer. Also drop the tablet auto-collapse effect in knowledge/index.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/frontend/client/src/components/Nav/Nav.tsx

@@ -1,6 +1,6 @@
 import type { ConversationListResponse } from '~/types/chat';
 import { PermissionTypes, Permissions } from '~/types/chat';
-import { memo, useCallback, useEffect, useLayoutEffect, useMemo, useRef, useState } from 'react';
+import { memo, useCallback, useEffect, useMemo, useState } from 'react';
 import { useSearchContext } from '~/Providers';
 import { Conversations } from '~/components/Conversations';
 import { Spinner } from '~/components/svg';
@@ -15,7 +15,6 @@ import {
 } from '~/hooks';
 import { cn } from '~/utils';
 import AccountSettings from './AccountSettings';
-import NavToggle from './NavToggle';
 import NewChat from './NewChat';
 import { ChatNavUserFooter } from './ChatNavUserFooter';
 
@@ -30,9 +29,6 @@ const Nav = ({
   const { isAuthenticated } = useAuthContext();
 
   const [navWidth, setNavWidth] = useState('240px');
-  const [isHovering, setIsHovering] = useState(false);
-  const navPanelRef = useRef<HTMLDivElement>(null);
-  const [navPanelRightPx, setNavPanelRightPx] = useState(0);
   const isSmallScreen = usePrefersMobileLayout();
   const [newUser, setNewUser] = useLocalStorage('newUser', true);
 
@@ -54,28 +50,6 @@ const Nav = ({
     }
   }, [isSmallScreen]);
 
-  // 折叠把手贴在会话列表右缘（分隔线右侧），需计入 MainLayout 窄轨 + main 内边距，故用测量值而非假定 left:0 + translateX
-  useLayoutEffect(() => {
-    if (isSmallScreen) {
-      return;
-    }
-    const el = navPanelRef.current;
-    if (!el) {
-      return;
-    }
-    const sync = () => {
-      setNavPanelRightPx(el.getBoundingClientRect().right);
-    };
-    sync();
-    const ro = new ResizeObserver(sync);
-    ro.observe(el);
-    window.addEventListener('resize', sync);
-    return () => {
-      ro.disconnect();
-      window.removeEventListener('resize', sync);
-    };
-  }, [isSmallScreen, navVisible, navWidth]);
-
   const [showLoading, setShowLoading] = useState(false);
 
   const { pageNumber, searchQuery, setPageNumber, searchQueryRes } = useSearchContext();
@@ -145,7 +119,6 @@ const Nav = ({
   return (
     <>
       <div
-        ref={navPanelRef}
         data-testid="nav"
         className={cn(
           // 须与 usePrefersMobileLayout（max-width:767px）一致：touch-mobile 为 max-1023，误伤 768–1023 会去掉边距/边框，像「盖在内容上」
@@ -153,8 +126,10 @@ const Nav = ({
           isSmallScreen && 'fixed inset-y-0 left-0 z-[70] h-[100dvh] shadow-[4px_0_24px_rgba(0,0,0,0.06)]',
         )}
         style={{
-          width: navVisible ? navWidth : '0px',
-          visibility: navVisible ? 'visible' : 'hidden',
+          // Desktop: sidebar is always docked/visible (collapse removed).
+          // Mobile: still a toggleable overlay drawer.
+          width: isSmallScreen ? (navVisible ? navWidth : '0px') : navWidth,
+          visibility: isSmallScreen ? (navVisible ? 'visible' : 'hidden') : 'visible',
           transition: 'width 0.2s, visibility 0.2s',
         }}
       >
@@ -228,16 +203,6 @@ const Nav = ({
           </div>
         </div>
       </div>
-      {!isSmallScreen && navPanelRightPx > 0 ? (
-        <NavToggle
-          navVisible={navVisible}
-          onToggle={toggleNavVisible}
-          isHovering={isHovering}
-          setIsHovering={setIsHovering}
-          className=""
-          anchorRightEdgePx={navPanelRightPx}
-        />
-      ) : null}
       {isSmallScreen && (
         <div
           id="mobile-nav-mask-toggle"

src/frontend/client/src/pages/knowledge/index.tsx

@@ -166,12 +166,6 @@ export default function Knowledge() {
         if (!isH5) setSpaceListDrawerOpen(false);
     }, [isH5]);
 
-    // Tablet (768–1023): collapse the sidebar by default so the file area gets the room,
-    // while the NavToggle stays available to expand it. Desktop keeps the user's choice.
-    useEffect(() => {
-        if (!isH5 && !isDesktop) setSidebarCollapsed(true);
-    }, [isH5, isDesktop]);
-
     useEffect(() => {
         if (showKnowledgeSquare) setSpaceListDrawerOpen(false);
     }, [showKnowledgeSquare]);

src/frontend/client/src/pages/knowledge/sidebar/KnowledgeSpaceSidebar.tsx

@@ -7,7 +7,6 @@ import { useEffect, useMemo, useRef, useState } from "react";
 import { useQuery, useQueryClient } from "@tanstack/react-query";
 import { KnowledgeSpace, SpaceRole, SpaceSortType, getMineSpacesApi, getJoinedSpacesApi, getDepartmentSpacesApi } from "~/api/knowledge";
 import { Button } from "~/components/ui/Button";
-import NavToggle from "~/components/Nav/NavToggle";
 import KnowledgeSpaceItem from "./KnowledgeSpaceItem";
 import KnowledgeSpaceCardItem from "./KnowledgeSpaceCardItem";
 import { SectionHeader } from "./SectionHeader";
@@ -148,7 +147,6 @@ export function KnowledgeSpaceSidebar({
     // Scrolling container ref — drives the dynamic, scroll-following name ellipsis.
     const listScrollRef = useRef<HTMLDivElement>(null);
     useDynamicEllipsis(listScrollRef);
-    const [isToggleHovering, setIsToggleHovering] = useState(false);
 
     const queryClient = useQueryClient();
 
@@ -610,8 +608,6 @@ export function KnowledgeSpaceSidebar({
                     onMouseDown={handleResizeStart}
                     onDoubleClick={handleResizeReset}
                     className={cn(
-                        // z below NavToggle (z-40) so the collapse button keeps capturing clicks
-                        // in its small area; everywhere else along the edge the resize handle wins.
                         "absolute top-0 z-[35] h-full w-[6px] -translate-x-1/2 cursor-col-resize",
                         // Subtle visual feedback: thin accent line on hover/active.
                         "after:absolute after:right-1/2 after:top-0 after:h-full after:w-px after:translate-x-1/2",
@@ -621,15 +617,6 @@ export function KnowledgeSpaceSidebar({
                     style={{ left: sidebarWidth }}
                 />
             )}
-            <NavToggle
-                navVisible={!collapsed}
-                onToggle={() => setCollapsed(!collapsed)}
-                isHovering={isToggleHovering}
-                setIsHovering={setIsToggleHovering}
-                className={`absolute top-1/2 left-0 z-[40] ${fullWidthMode ? "hidden" : ""}`}
-                translateX={collapsed ? 0 : sidebarWidth}
-                disableTransition={isResizing}
-            />
         </div>
     );
 }