fix: read project scope from router params; align sidebar header icons

- useSelectMention now reads the active project from React Router's search
  params instead of window.location, which can drift out of sync because
  new-chat params are written to the URL via raw history.pushState; the
  Model Selector and @ command now reliably keep the project on switch
- Move the Chats section header out of the virtualized list so it renders
  in the same context as the Projects header and isn't shifted by the
  list scrollbar
- Inset header action icons (pr-2) so Projects/Chats header icons line up
  with the project-row and conversation-row trailing actions
- Extract getRouteChatProjectId into utils for the submit path

client/src/components/Conversations/Conversations.tsx

@@ -102,7 +102,7 @@ const ChatsHeader: FC<ChatsHeaderProps> = memo(({ isExpanded, onToggle }) => {
   }, [conversation?.conversationId, newConversation, queryClient]);
 
   return (
-    <div className="flex h-8 w-full items-center gap-0.5">
+    <div className="flex h-8 w-full items-center gap-0.5 pr-2">
       <button
         onClick={onToggle}
         className="group flex min-w-0 flex-1 items-center gap-1 rounded-lg px-1 py-2 text-xs font-bold text-text-secondary outline-none focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-inset focus-visible:ring-black dark:focus-visible:ring-white"
@@ -156,7 +156,6 @@ DateLabel.displayName = 'DateLabel';
 
 type FlattenedItem =
   | { type: 'favorites' }
-  | { type: 'chats-header' }
   | { type: 'header'; groupName: string }
   | { type: 'convo'; convo: TConversation }
   | { type: 'loading' };
@@ -244,7 +243,6 @@ const Conversations: FC<ConversationsProps> = ({
     if (shouldShowFavorites) {
       items.push({ type: 'favorites' });
     }
-    items.push({ type: 'chats-header' });
 
     if (isChatsExpanded) {
       groupedConversations.forEach(([groupName, convos]) => {
@@ -277,9 +275,6 @@ const Conversations: FC<ConversationsProps> = ({
           if (item.type === 'favorites') {
             return `favorites-${favoritesContentKeyRef.current}`;
           }
-          if (item.type === 'chats-header') {
-            return 'chats-header';
-          }
           if (item.type === 'header') {
             return `header-${item.groupName}`;
           }
@@ -342,22 +337,9 @@ const Conversations: FC<ConversationsProps> = ({
         );
       }
 
-      if (item.type === 'chats-header') {
-        return (
-          <MeasuredRow key={key} {...rowProps}>
-            <ChatsHeader
-              isExpanded={isChatsExpanded}
-              onToggle={() => setIsChatsExpanded(!isChatsExpanded)}
-            />
-          </MeasuredRow>
-        );
-      }
-
       if (item.type === 'header') {
-        // First date header index depends on whether favorites row is included
-        // With favorites: [favorites, chats-header, first-header] → index 2
-        // Without favorites: [chats-header, first-header] → index 1
-        const firstHeaderIndex = shouldShowFavorites ? 2 : 1;
+        // First date header index depends on whether the favorites row is included
+        const firstHeaderIndex = shouldShowFavorites ? 1 : 0;
         return (
           <MeasuredRow key={key} {...rowProps}>
             <DateLabel groupName={item.groupName} isFirst={index === firstHeaderIndex} />
@@ -381,17 +363,7 @@ const Conversations: FC<ConversationsProps> = ({
 
       return null;
     },
-    [
-      cache,
-      flattenedItems,
-      moveToTop,
-      toggleNav,
-      isSmallScreen,
-      isChatsExpanded,
-      setIsChatsExpanded,
-      shouldShowFavorites,
-      activeJobIds,
-    ],
+    [cache, flattenedItems, moveToTop, toggleNav, isSmallScreen, shouldShowFavorites, activeJobIds],
   );
 
   const getRowHeight = useCallback(
@@ -415,6 +387,12 @@ const Conversations: FC<ConversationsProps> = ({
 
   return (
     <div className="relative flex h-full min-h-0 flex-col pb-2 text-sm text-text-primary">
+      <div className="px-3">
+        <ChatsHeader
+          isExpanded={isChatsExpanded}
+          onToggle={() => setIsChatsExpanded(!isChatsExpanded)}
+        />
+      </div>
       {isSearchLoading ? (
         <div className="flex flex-1 items-center justify-center">
           <Spinner className="text-text-primary" />

client/src/components/Conversations/ProjectsSection.tsx

@@ -452,7 +452,7 @@ const ProjectsSection = ({ toggleNav, isAuthenticated }: ProjectsSectionProps) =
 
   return (
     <div className="flex flex-col px-3 text-sm">
-      <div className="flex h-8 w-full items-center gap-0.5">
+      <div className="flex h-8 w-full items-center gap-0.5 pr-2">
         <button
           onClick={() => setIsExpanded(!isExpanded)}
           className="group flex min-w-0 flex-1 items-center gap-1 rounded-lg px-1 py-2 text-xs font-bold text-text-secondary outline-none focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-inset focus-visible:ring-black dark:focus-visible:ring-white"

client/src/hooks/Chat/useChatFunctions.ts

@@ -28,7 +28,7 @@ import type { SetterOrUpdater } from 'recoil';
 import type { TAskFunction, ExtendedFile } from '~/common';
 import useSetFilesToDelete from '~/hooks/Files/useSetFilesToDelete';
 import useGetSender from '~/hooks/Conversations/useGetSender';
-import { logger, createDualMessageContent } from '~/utils';
+import { logger, createDualMessageContent, getRouteChatProjectId } from '~/utils';
 import store, { useGetEphemeralAgent } from '~/store';
 import { startupConfigKey } from '~/data-provider';
 import useUserKey from '~/hooks/Input/useUserKey';
@@ -40,15 +40,6 @@ const logChatRequest = (request: Record<string, unknown>) => {
   logger.log('=====================================');
 };
 
-const getRouteChatProjectId = () => {
-  if (typeof window === 'undefined') {
-    return null;
-  }
-
-  const projectId = new URLSearchParams(window.location.search).get('projectId');
-  return projectId != null && /^[a-f\d]{24}$/i.test(projectId) ? projectId : null;
-};
-
 export default function useChatFunctions({
   index = 0,
   files,

client/src/hooks/Input/useSelectMention.ts

@@ -1,5 +1,6 @@
-import { useCallback } from 'react';
+import { useCallback, useMemo } from 'react';
 import { useRecoilValue } from 'recoil';
+import { useSearchParams } from 'react-router-dom';
 import { EModelEndpoint, isAgentsEndpoint, isAssistantsEndpoint } from 'librechat-data-provider';
 import type {
   TPreset,
@@ -39,6 +40,16 @@ export default function useSelectMention({
   const getDefaultConversation = useDefaultConvo();
   const modularChat = useRecoilValue(store.modularChat);
   const availableTools = useRecoilValue(store.availableTools);
+  const [searchParams] = useSearchParams();
+  /**
+   * Project scope is read from React Router's search params (the same source the
+   * project chip reads), not window.location — new-chat params are written to the
+   * URL via raw history.pushState, so window.location can drift out of sync.
+   */
+  const routeChatProjectId = useMemo(() => {
+    const projectId = searchParams.get('projectId');
+    return projectId != null && /^[a-f\d]{24}$/i.test(projectId) ? projectId : null;
+  }, [searchParams]);
 
   const onSelectSpec = useCallback(
     (spec?: TModelSpec) => {
@@ -109,7 +120,7 @@ export default function useSelectMention({
       newConversation({
         template: {
           ...(template as Partial<TConversation>),
-          chatProjectId: conversation?.chatProjectId ?? null,
+          chatProjectId: routeChatProjectId,
         },
         preset,
         keepAddedConvos: isModular,
@@ -122,6 +133,7 @@ export default function useSelectMention({
       newConversation,
       endpointsConfig,
       assistantsMap,
+      routeChatProjectId,
     ],
   );
 
@@ -206,13 +218,20 @@ export default function useSelectMention({
       newConversation({
         template: {
           ...(template as Partial<TConversation>),
-          chatProjectId: conversation?.chatProjectId ?? null,
+          chatProjectId: routeChatProjectId,
         },
         preset: { ...kwargs, spec: null, iconURL: null, modelLabel: null, endpoint: newEndpoint },
         keepAddedConvos: isNewModular,
       });
     },
-    [getConversation, getDefaultConversation, modularChat, newConversation, endpointsConfig],
+    [
+      getConversation,
+      getDefaultConversation,
+      modularChat,
+      newConversation,
+      endpointsConfig,
+      routeChatProjectId,
+    ],
   );
 
   const onSelectPreset = useCallback(
@@ -270,7 +289,7 @@ export default function useSelectMention({
 
       logger.info('conversation', 'Switching conversation to new preset', template);
       newConversation({
-        template: { chatProjectId: conversation?.chatProjectId ?? null },
+        template: { chatProjectId: routeChatProjectId },
         preset: newPreset,
         keepAddedConvos: isModular,
         disableParams,
@@ -283,6 +302,7 @@ export default function useSelectMention({
       newConversation,
       endpointsConfig,
       getDefaultConversation,
+      routeChatProjectId,
     ],
   );
 

client/src/utils/convos.ts

@@ -167,6 +167,18 @@ function conversationMatchesProjectQuery(
   return conversation.chatProjectId === projectId;
 }
 
+/**
+ * Reads the project id from the current URL's `?projectId` param — the source of
+ * truth for a new chat's project scope (the conversation atom can lag behind it).
+ */
+export function getRouteChatProjectId(): string | null {
+  if (typeof window === 'undefined') {
+    return null;
+  }
+  const projectId = new URLSearchParams(window.location.search).get('projectId');
+  return projectId != null && /^[a-f\d]{24}$/i.test(projectId) ? projectId : null;
+}
+
 // === InfiniteData helpers for cursor-based convo queries ===
 
 export function findConversationInInfinite(