feat: add Tasks pill to reopen collapsed task lane

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/pages/AssistantChatPage.tsx

@@ -1,6 +1,6 @@
 import { useState, useEffect, useRef, useCallback } from 'react'
 import { useLocation, useNavigate, useParams } from 'react-router-dom'
-import { Sparkles, Send, Loader2, Flag, MessageSquare, Paperclip, Terminal, X, RotateCcw, ImagePlus } from 'lucide-react'
+import { Sparkles, Send, Loader2, Flag, MessageSquare, Paperclip, Terminal, X, RotateCcw, ImagePlus, ListChecks } from 'lucide-react'
 import { cn } from '@/lib/utils'
 import { uploadsApi } from '@/api/uploads'
 import type { PendingUpload } from '@/types/upload'
@@ -12,7 +12,7 @@ import { analytics } from '@/lib/analytics'
 import { toast } from '@/lib/toast'
 import { ChatSidebar, ChatSidebarCollapsedBar } from '@/components/assistant/ChatSidebar'
 import { ChatMessage } from '@/components/assistant/ChatMessage'
-import { TaskLane, clearTaskState } from '@/components/assistant/TaskLane'
+import { TaskLane } from '@/components/assistant/TaskLane'
 import { ConcludeSessionModal } from '@/components/assistant/ConcludeSessionModal'
 import type { ChatListItem, ConclusionOutcome } from '@/types/assistant-chat'
 import type { SuggestedFlow } from '@/types/copilot'
@@ -758,6 +758,17 @@ export default function AssistantChatPage() {
                           <span className="hidden sm:inline">Conclude</span>
                         </button>
                       )}
+                      {!showTaskLane && (activeQuestions.length > 0 || activeActions.length > 0) && (
+                        <button
+                          type="button"
+                          onClick={() => setShowTaskLane(true)}
+                          className="flex items-center gap-1.5 rounded-lg px-2 py-1.5 text-xs text-accent-text hover:text-foreground hover:bg-accent-dim transition-colors"
+                          title="Show task panel"
+                        >
+                          <ListChecks size={14} />
+                          Tasks ({activeQuestions.length + activeActions.length})
+                        </button>
+                      )}
                     </div>
                     <button type="button" onClick={handleSend} disabled={!input.trim() || loading} className={cn(
                       'flex h-8 w-8 items-center justify-center rounded-lg transition-all',