ChatTabBar: + button dropdown to add chat / terminal / agent pane

Replaces single onNewChat handler with onAddPane(kind). Terminal pane
header gets matching + dropdown. Context menu "New chat" stays.

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

apps/web/src/components/ChatTabBar.tsx

@@ -1,5 +1,5 @@
 import { useState } from 'react';
-import { History, MessageSquare, Plus, X } from 'lucide-react';
+import { Bot, History, MessageSquare, Plus, Terminal, X } from 'lucide-react';
 import type { Chat, WorkspacePane } from '@/api/types';
 import { StatusDot } from '@/components/StatusDot';
 import {
@@ -9,6 +9,12 @@ import {
   ContextMenuSeparator,
   ContextMenuTrigger,
 } from '@/components/ui/context-menu';
+import {
+  DropdownMenu,
+  DropdownMenuContent,
+  DropdownMenuItem,
+  DropdownMenuTrigger,
+} from '@/components/ui/dropdown-menu';
 import { useLongPress } from '@/hooks/useLongPress';
 import { cn } from '@/lib/utils';
 
@@ -20,7 +26,7 @@ interface Props {
   onCloseOthers: (chatId: string) => void;
   onCloseToRight: (chatId: string) => void;
   onCloseAll: () => void;
-  onNewChat: () => void;
+  onAddPane: (kind: 'chat' | 'terminal' | 'agent') => void;
   onShowHistory: () => void;
   onRename: (chatId: string, name: string) => Promise<void>;
   onRemovePane?: () => void;
@@ -34,7 +40,7 @@ export function ChatTabBar({
   onCloseOthers,
   onCloseToRight,
   onCloseAll,
-  onNewChat,
+  onAddPane,
   onShowHistory,
   onRename,
   onRemovePane,
@@ -125,7 +131,7 @@ export function ChatTabBar({
               </div>
             </ContextMenuTrigger>
             <ContextMenuContent>
-              <ContextMenuItem onSelect={() => onNewChat()}>
+              <ContextMenuItem onSelect={() => onAddPane('chat')}>
                 New chat
               </ContextMenuItem>
               <ContextMenuSeparator />
@@ -164,15 +170,29 @@ export function ChatTabBar({
       )}
 
       <div className="flex items-center ml-auto gap-0.5 px-1 shrink-0">
-        <button
-          type="button"
-          onClick={onNewChat}
-          className="inline-flex items-center justify-center p-1 rounded text-muted-foreground hover:bg-muted hover:text-foreground max-md:min-h-[44px] max-md:min-w-[44px]"
-          aria-label="New chat"
-          title="New chat"
-        >
-          <Plus size={12} />
-        </button>
+        <DropdownMenu>
+          <DropdownMenuTrigger asChild>
+            <button
+              type="button"
+              className="inline-flex items-center justify-center p-1 rounded text-muted-foreground hover:bg-muted hover:text-foreground max-md:min-h-[44px] max-md:min-w-[44px]"
+              aria-label="New pane"
+              title="New pane"
+            >
+              <Plus size={12} />
+            </button>
+          </DropdownMenuTrigger>
+          <DropdownMenuContent align="end" className="min-w-40">
+            <DropdownMenuItem onSelect={() => onAddPane('chat')}>
+              <MessageSquare size={14} /> New chat
+            </DropdownMenuItem>
+            <DropdownMenuItem onSelect={() => onAddPane('terminal')}>
+              <Terminal size={14} /> New terminal
+            </DropdownMenuItem>
+            <DropdownMenuItem onSelect={() => onAddPane('agent')}>
+              <Bot size={14} /> New agent
+            </DropdownMenuItem>
+          </DropdownMenuContent>
+        </DropdownMenu>
         <button
           type="button"
           onClick={onShowHistory}