feat: kanban board view with drag-and-drop status changes

- New KanbanBoard component with 4 columns: Active, Queued, Blocked, Done
- HTML5 drag-and-drop to move tasks between status columns
- Visual drop zone highlighting and drag state
- Task cards show priority, project, assignee, due date, subtask progress
- View toggle (list/board) in Queue page header, persisted to localStorage
- Status filter hidden in board mode (columns serve as visual filter)
- Cards link to task detail pages, click opens detail panel

frontend/src/components/KanbanBoard.tsx

@@ -0,0 +1,316 @@
+import { useState, useCallback, useMemo } from "react";
+import { Link } from "react-router-dom";
+import type { Task, TaskStatus } from "../lib/types";
+
+interface KanbanColumn {
+  status: TaskStatus;
+  label: string;
+  icon: string;
+  color: string;
+  bgColor: string;
+  borderColor: string;
+  dropColor: string;
+}
+
+const COLUMNS: KanbanColumn[] = [
+  {
+    status: "active",
+    label: "Active",
+    icon: "⚡",
+    color: "text-amber-700",
+    bgColor: "bg-amber-50",
+    borderColor: "border-amber-200",
+    dropColor: "bg-amber-100",
+  },
+  {
+    status: "queued",
+    label: "Queued",
+    icon: "📋",
+    color: "text-blue-700",
+    bgColor: "bg-blue-50",
+    borderColor: "border-blue-200",
+    dropColor: "bg-blue-100",
+  },
+  {
+    status: "blocked",
+    label: "Blocked",
+    icon: "🚫",
+    color: "text-red-700",
+    bgColor: "bg-red-50",
+    borderColor: "border-red-200",
+    dropColor: "bg-red-100",
+  },
+  {
+    status: "completed",
+    label: "Done",
+    icon: "✅",
+    color: "text-green-700",
+    bgColor: "bg-green-50",
+    borderColor: "border-green-200",
+    dropColor: "bg-green-100",
+  },
+];
+
+const PRIORITY_COLORS: Record<string, string> = {
+  critical: "bg-red-100 text-red-700 border-red-200",
+  high: "bg-orange-100 text-orange-700 border-orange-200",
+  medium: "bg-blue-100 text-blue-700 border-blue-200",
+  low: "bg-gray-100 text-gray-500 border-gray-200",
+};
+
+interface KanbanCardProps {
+  task: Task;
+  projectName?: string;
+  onDragStart: (taskId: string) => void;
+  onDragEnd: () => void;
+  isDragging: boolean;
+  onClick: () => void;
+}
+
+function KanbanCard({ task, projectName, onDragStart, onDragEnd, isDragging, onClick }: KanbanCardProps) {
+  const subtasksDone = task.subtasks?.filter((s) => s.completed).length ?? 0;
+  const subtasksTotal = task.subtasks?.length ?? 0;
+
+  return (
+    <div
+      draggable
+      onDragStart={(e) => {
+        e.dataTransfer.setData("text/plain", task.id);
+        e.dataTransfer.effectAllowed = "move";
+        onDragStart(task.id);
+      }}
+      onDragEnd={onDragEnd}
+      onClick={onClick}
+      className={`bg-white rounded-lg border border-gray-200 p-3 cursor-grab active:cursor-grabbing shadow-sm hover:shadow-md transition-all ${
+        isDragging ? "opacity-40 scale-95" : "opacity-100"
+      }`}
+    >
+      {/* Header: number + priority */}
+      <div className="flex items-center justify-between mb-1.5">
+        <Link
+          to={`/task/HQ-${task.taskNumber}`}
+          onClick={(e) => e.stopPropagation()}
+          className="text-xs font-bold font-mono text-gray-500 hover:text-amber-600 transition"
+        >
+          HQ-{task.taskNumber}
+        </Link>
+        <span className={`text-[10px] font-medium px-1.5 py-0.5 rounded-full border ${PRIORITY_COLORS[task.priority] || PRIORITY_COLORS.medium}`}>
+          {task.priority}
+        </span>
+      </div>
+
+      {/* Title */}
+      <h4 className="text-sm font-medium text-gray-900 leading-snug mb-1.5 line-clamp-2">
+        {task.title}
+      </h4>
+
+      {/* Meta: project, assignee, subtasks, due */}
+      <div className="flex flex-wrap gap-1.5 items-center">
+        {projectName && (
+          <span className="text-[10px] text-sky-600 bg-sky-50 px-1.5 py-0.5 rounded-full">
+            📁 {projectName}
+          </span>
+        )}
+        {task.assigneeName && (
+          <span className="text-[10px] text-emerald-600 bg-emerald-50 px-1.5 py-0.5 rounded-full">
+            👤 {task.assigneeName}
+          </span>
+        )}
+        {task.dueDate && (() => {
+          const due = new Date(task.dueDate);
+          const diffMs = due.getTime() - Date.now();
+          const diffDays = Math.ceil(diffMs / (1000 * 60 * 60 * 24));
+          const isOverdue = diffMs < 0;
+          const label = isOverdue ? "overdue" : diffDays === 0 ? "today" : diffDays === 1 ? "tomorrow" : `${diffDays}d`;
+          return (
+            <span className={`text-[10px] px-1.5 py-0.5 rounded-full ${
+              isOverdue ? "bg-red-100 text-red-600" : diffDays <= 2 ? "bg-amber-100 text-amber-600" : "bg-gray-100 text-gray-500"
+            }`}>
+              📅 {label}
+            </span>
+          );
+        })()}
+      </div>
+
+      {/* Subtask progress */}
+      {subtasksTotal > 0 && (
+        <div className="mt-2 flex items-center gap-2">
+          <div className="flex-1 bg-gray-100 rounded-full h-1">
+            <div
+              className="bg-green-500 h-1 rounded-full transition-all"
+              style={{ width: `${(subtasksDone / subtasksTotal) * 100}%` }}
+            />
+          </div>
+          <span className="text-[10px] text-gray-400">{subtasksDone}/{subtasksTotal}</span>
+        </div>
+      )}
+    </div>
+  );
+}
+
+interface KanbanColumnProps {
+  column: KanbanColumn;
+  tasks: Task[];
+  projectMap: Record<string, string>;
+  draggingId: string | null;
+  onDragStart: (taskId: string) => void;
+  onDragEnd: () => void;
+  onDrop: (taskId: string, status: TaskStatus) => void;
+  onCardClick: (taskId: string) => void;
+}
+
+function KanbanColumnView({
+  column,
+  tasks,
+  projectMap,
+  draggingId,
+  onDragStart,
+  onDragEnd,
+  onDrop,
+  onCardClick,
+}: KanbanColumnProps) {
+  const [dragOver, setDragOver] = useState(false);
+
+  const handleDragOver = useCallback((e: React.DragEvent) => {
+    e.preventDefault();
+    e.dataTransfer.dropEffect = "move";
+    setDragOver(true);
+  }, []);
+
+  const handleDragLeave = useCallback(() => {
+    setDragOver(false);
+  }, []);
+
+  const handleDrop = useCallback(
+    (e: React.DragEvent) => {
+      e.preventDefault();
+      setDragOver(false);
+      const taskId = e.dataTransfer.getData("text/plain");
+      if (taskId) {
+        onDrop(taskId, column.status);
+      }
+    },
+    [column.status, onDrop]
+  );
+
+  return (
+    <div
+      className={`flex flex-col rounded-xl border ${column.borderColor} ${
+        dragOver ? column.dropColor : column.bgColor
+      } transition-colors min-h-[200px]`}
+      onDragOver={handleDragOver}
+      onDragLeave={handleDragLeave}
+      onDrop={handleDrop}
+    >
+      {/* Column header */}
+      <div className={`px-3 py-2.5 border-b ${column.borderColor} flex items-center justify-between`}>
+        <div className="flex items-center gap-1.5">
+          <span className="text-sm">{column.icon}</span>
+          <h3 className={`text-sm font-semibold ${column.color}`}>{column.label}</h3>
+        </div>
+        <span className={`text-xs font-medium ${column.color} opacity-70`}>
+          {tasks.length}
+        </span>
+      </div>
+
+      {/* Cards */}
+      <div className="flex-1 p-2 space-y-2 overflow-y-auto max-h-[calc(100vh-16rem)]">
+        {tasks.length === 0 ? (
+          <div className="text-xs text-gray-400 text-center py-6 italic">
+            {dragOver ? "Drop here" : "No tasks"}
+          </div>
+        ) : (
+          tasks.map((task) => (
+            <KanbanCard
+              key={task.id}
+              task={task}
+              projectName={task.projectId ? projectMap[task.projectId] : undefined}
+              onDragStart={onDragStart}
+              onDragEnd={onDragEnd}
+              isDragging={draggingId === task.id}
+              onClick={() => onCardClick(task.id)}
+            />
+          ))
+        )}
+        {dragOver && tasks.length > 0 && (
+          <div className={`border-2 border-dashed ${column.borderColor} rounded-lg p-4 text-center text-xs ${column.color} opacity-50`}>
+            Drop here
+          </div>
+        )}
+      </div>
+    </div>
+  );
+}
+
+interface KanbanBoardProps {
+  tasks: Task[];
+  projectMap: Record<string, string>;
+  onStatusChange: (taskId: string, status: TaskStatus) => void;
+  onCardClick: (taskId: string) => void;
+  search: string;
+  filterPriority: string;
+}
+
+export function KanbanBoard({
+  tasks,
+  projectMap,
+  onStatusChange,
+  onCardClick,
+  search,
+  filterPriority,
+}: KanbanBoardProps) {
+  const [draggingId, setDraggingId] = useState<string | null>(null);
+
+  const filteredTasks = useMemo(() => {
+    let filtered = tasks;
+    if (search.trim()) {
+      const q = search.toLowerCase();
+      filtered = filtered.filter(
+        (t) =>
+          t.title.toLowerCase().includes(q) ||
+          (t.description && t.description.toLowerCase().includes(q)) ||
+          (t.taskNumber && `hq-${t.taskNumber}`.includes(q)) ||
+          (t.assigneeName && t.assigneeName.toLowerCase().includes(q))
+      );
+    }
+    if (filterPriority) {
+      filtered = filtered.filter((t) => t.priority === filterPriority);
+    }
+    return filtered;
+  }, [tasks, search, filterPriority]);
+
+  const tasksByStatus = useMemo(() => {
+    const map: Record<string, Task[]> = {};
+    for (const col of COLUMNS) {
+      map[col.status] = filteredTasks.filter((t) => t.status === col.status);
+    }
+    return map;
+  }, [filteredTasks]);
+
+  const handleDrop = useCallback(
+    (taskId: string, newStatus: TaskStatus) => {
+      const task = tasks.find((t) => t.id === taskId);
+      if (!task || task.status === newStatus) return;
+      onStatusChange(taskId, newStatus);
+    },
+    [tasks, onStatusChange]
+  );
+
+  return (
+    <div className="grid grid-cols-1 sm:grid-cols-2 lg:grid-cols-4 gap-3 px-4 sm:px-6 py-4">
+      {COLUMNS.map((column) => (
+        <KanbanColumnView
+          key={column.status}
+          column={column}
+          tasks={tasksByStatus[column.status] || []}
+          projectMap={projectMap}
+          draggingId={draggingId}
+          onDragStart={setDraggingId}
+          onDragEnd={() => setDraggingId(null)}
+          onDrop={handleDrop}
+          onCardClick={onCardClick}
+        />
+      ))}
+    </div>
+  );
+}

frontend/src/pages/QueuePage.tsx

@@ -4,10 +4,13 @@ import { useCurrentUser } from "../hooks/useCurrentUser";
 import { TaskCard } from "../components/TaskCard";
 import { TaskDetailPanel } from "../components/TaskDetailPanel";
 import { CreateTaskModal } from "../components/CreateTaskModal";
+import { KanbanBoard } from "../components/KanbanBoard";
 import { useToast } from "../components/Toast";
 import { updateTask, reorderTasks, createTask, fetchProjects } from "../lib/api";
 import type { TaskStatus, Project } from "../lib/types";
 
+type ViewMode = "list" | "board";
+
 export function QueuePage() {
   const { tasks, loading, error, refresh } = useTasks(5000);
   const { isAuthenticated } = useCurrentUser();
@@ -17,9 +20,17 @@ export function QueuePage() {
   const [search, setSearch] = useState("");
   const [filterPriority, setFilterPriority] = useState<string>("");
   const [filterStatus, setFilterStatus] = useState<string>("");
+  const [viewMode, setViewMode] = useState<ViewMode>(() => {
+    return (localStorage.getItem("hammer-queue-view") as ViewMode) || "list";
+  });
   const [projects, setProjects] = useState<Project[]>([]);
   const { toast } = useToast();
 
+  // Persist view mode
+  useEffect(() => {
+    localStorage.setItem("hammer-queue-view", viewMode);
+  }, [viewMode]);
+
   // Load projects for name display
   useEffect(() => {
     fetchProjects().then(setProjects).catch(() => {});
@@ -142,13 +153,38 @@ export function QueuePage() {
                 )}
               </p>
             </div>
-            <button
-              onClick={() => setShowCreate(true)}
-              className="text-sm bg-amber-500 text-white px-3 sm:px-4 py-2 rounded-lg hover:bg-amber-600 transition font-medium"
-              title="Ctrl+N"
-            >
-              + New
-            </button>
+            <div className="flex items-center gap-2">
+              {/* View toggle */}
+              <div className="hidden sm:flex items-center bg-gray-100 rounded-lg p-0.5">
+                <button
+                  onClick={() => setViewMode("list")}
+                  className={`p-1.5 rounded-md transition ${viewMode === "list" ? "bg-white shadow-sm text-amber-600" : "text-gray-400 hover:text-gray-600"}`}
+                  title="List view"
+                  aria-label="List view"
+                >
+                  <svg className="w-4 h-4" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+                    <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M4 6h16M4 10h16M4 14h16M4 18h16" />
+                  </svg>
+                </button>
+                <button
+                  onClick={() => setViewMode("board")}
+                  className={`p-1.5 rounded-md transition ${viewMode === "board" ? "bg-white shadow-sm text-amber-600" : "text-gray-400 hover:text-gray-600"}`}
+                  title="Board view"
+                  aria-label="Board view"
+                >
+                  <svg className="w-4 h-4" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+                    <path strokeLinecap="round" strokeLinejoin="round" strokeWidth={2} d="M9 17V7m0 10a2 2 0 01-2 2H5a2 2 0 01-2-2V7a2 2 0 012-2h2a2 2 0 012 2m0 10a2 2 0 002 2h2a2 2 0 002-2M9 7a2 2 0 012-2h2a2 2 0 012 2m0 10V7m0 10a2 2 0 002 2h2a2 2 0 002-2V7a2 2 0 00-2-2h-2a2 2 0 00-2 2" />
+                  </svg>
+                </button>
+              </div>
+              <button
+                onClick={() => setShowCreate(true)}
+                className="text-sm bg-amber-500 text-white px-3 sm:px-4 py-2 rounded-lg hover:bg-amber-600 transition font-medium"
+                title="Ctrl+N"
+              >
+                + New
+              </button>
+            </div>
           </div>
           <div className="flex gap-2 items-center">
             <div className="flex-1 relative">
@@ -184,18 +220,20 @@ export function QueuePage() {
               <option value="medium">🔵 Medium</option>
               <option value="low">⚪ Low</option>
             </select>
-            <select
-              value={filterStatus}
-              onChange={(e) => setFilterStatus(e.target.value)}
-              className="text-sm border border-gray-200 rounded-lg px-3 py-2 focus:outline-none focus:ring-2 focus:ring-amber-200 bg-white"
-            >
-              <option value="">All statuses</option>
-              <option value="active">⚡ Active</option>
-              <option value="queued">📋 Queued</option>
-              <option value="blocked">🚫 Blocked</option>
-              <option value="completed">✅ Completed</option>
-              <option value="cancelled">❌ Cancelled</option>
-            </select>
+            {viewMode === "list" && (
+              <select
+                value={filterStatus}
+                onChange={(e) => setFilterStatus(e.target.value)}
+                className="text-sm border border-gray-200 rounded-lg px-3 py-2 focus:outline-none focus:ring-2 focus:ring-amber-200 bg-white"
+              >
+                <option value="">All statuses</option>
+                <option value="active">⚡ Active</option>
+                <option value="queued">📋 Queued</option>
+                <option value="blocked">🚫 Blocked</option>
+                <option value="completed">✅ Completed</option>
+                <option value="cancelled">❌ Cancelled</option>
+              </select>
+            )}
             {activeFilters > 0 && (
               <button
                 onClick={() => { setFilterPriority(""); setFilterStatus(""); }}
@@ -215,122 +253,111 @@ export function QueuePage() {
         onCreate={handleCreate}
       />
 
-      <div className="max-w-4xl mx-auto px-4 sm:px-6 py-4 sm:py-6 space-y-5 sm:space-y-6">
-        {loading && (
-          <div className="text-center text-gray-400 py-12">Loading tasks...</div>
-        )}
-        {error && (
-          <div className="bg-red-50 border border-red-200 text-red-700 rounded-lg p-3 text-sm">
-            {error}
-          </div>
-        )}
-
-        {/* Active Task */}
-        {showSection("active") && (
-          <section>
-            <h2 className="text-sm font-semibold text-gray-500 uppercase tracking-wide mb-3">
-              ⚡ Currently Working On
-            </h2>
-            {activeTasks.length === 0 ? (
-              <div className="border-2 border-dashed border-gray-200 rounded-lg p-8 text-center text-gray-400">
-                No active task — Hammer is idle
-              </div>
-            ) : (
-              <div className="space-y-3">
-                {activeTasks.map((task) => (
-                  <TaskCard
-                    key={task.id}
-                    task={task}
-                    onStatusChange={handleStatusChange}
-                    isActive
-                    onClick={() => setSelectedTask(task.id)}
-                    projectName={task.projectId ? projectMap[task.projectId] : undefined}
-                  />
-                ))}
-              </div>
-            )}
-          </section>
-        )}
-
-        {/* Blocked */}
-        {showSection("blocked") && blockedTasks.length > 0 && (
-          <section>
-            <h2 className="text-sm font-semibold text-gray-500 uppercase tracking-wide mb-3">
-              🚫 Blocked ({blockedTasks.length})
-            </h2>
-            <div className="space-y-2">
-              {blockedTasks.map((task) => (
-                <TaskCard
-                  key={task.id}
-                  task={task}
-                  onStatusChange={handleStatusChange}
-                  onClick={() => setSelectedTask(task.id)}
-                  projectName={task.projectId ? projectMap[task.projectId] : undefined}
-                />
-              ))}
+      {viewMode === "board" ? (
+        <KanbanBoard
+          tasks={tasks}
+          projectMap={projectMap}
+          onStatusChange={handleStatusChange}
+          onCardClick={(id) => setSelectedTask(id)}
+          search={search}
+          filterPriority={filterPriority}
+        />
+      ) : (
+        <div className="max-w-4xl mx-auto px-4 sm:px-6 py-4 sm:py-6 space-y-5 sm:space-y-6">
+          {loading && (
+            <div className="text-center text-gray-400 py-12">Loading tasks...</div>
+          )}
+          {error && (
+            <div className="bg-red-50 border border-red-200 text-red-700 rounded-lg p-3 text-sm">
+              {error}
             </div>
-          </section>
-        )}
+          )}
 
-        {/* Queue */}
-        {showSection("queued") && (
-          <section>
-            <h2 className="text-sm font-semibold text-gray-500 uppercase tracking-wide mb-3">
-              📋 Queue ({queuedTasks.length})
-            </h2>
-            {queuedTasks.length === 0 ? (
-              <div className="border-2 border-dashed border-gray-200 rounded-lg p-6 text-center text-gray-400">
-                Queue is empty
-              </div>
-            ) : (
-              <div className="space-y-2">
-                {queuedTasks.map((task, i) => (
-                  <TaskCard
-                    key={task.id}
-                    task={task}
-                    onStatusChange={handleStatusChange}
-                    onMoveUp={() => handleMoveUp(i)}
-                    onMoveDown={() => handleMoveDown(i)}
-                    isFirst={i === 0}
-                    isLast={i === queuedTasks.length - 1}
-                    onClick={() => setSelectedTask(task.id)}
-                    projectName={task.projectId ? projectMap[task.projectId] : undefined}
-                  />
-                ))}
-              </div>
-            )}
-          </section>
-        )}
-
-        {/* Completed */}
-        {(showSection("completed") || showSection("cancelled")) && (
-          <section>
-            {filterStatus ? (
-              <>
-                <h2 className="text-sm font-semibold text-gray-500 uppercase tracking-wide mb-3">
-                  {filterStatus === "completed" ? "✅" : "❌"} {filterStatus.charAt(0).toUpperCase() + filterStatus.slice(1)} ({completedTasks.length})
-                </h2>
-                <div className="space-y-2 opacity-60">
-                  {completedTasks.map((task) => (
+          {/* Active Task */}
+          {showSection("active") && (
+            <section>
+              <h2 className="text-sm font-semibold text-gray-500 uppercase tracking-wide mb-3">
+                ⚡ Currently Working On
+              </h2>
+              {activeTasks.length === 0 ? (
+                <div className="border-2 border-dashed border-gray-200 rounded-lg p-8 text-center text-gray-400">
+                  No active task — Hammer is idle
+                </div>
+              ) : (
+                <div className="space-y-3">
+                  {activeTasks.map((task) => (
                     <TaskCard
                       key={task.id}
                       task={task}
                       onStatusChange={handleStatusChange}
+                      isActive
                       onClick={() => setSelectedTask(task.id)}
                       projectName={task.projectId ? projectMap[task.projectId] : undefined}
                     />
                   ))}
                 </div>
-              </>
-            ) : (
-              <>
-                <button
-                  onClick={() => setShowCompleted(!showCompleted)}
-                  className="text-sm font-semibold text-gray-500 uppercase tracking-wide mb-3 flex items-center gap-1 hover:text-gray-700"
-                >
-                  {showCompleted ? "▾" : "▸"} Completed / Cancelled ({completedTasks.length})
-                </button>
-                {showCompleted && (
+              )}
+            </section>
+          )}
+
+          {/* Blocked */}
+          {showSection("blocked") && blockedTasks.length > 0 && (
+            <section>
+              <h2 className="text-sm font-semibold text-gray-500 uppercase tracking-wide mb-3">
+                🚫 Blocked ({blockedTasks.length})
+              </h2>
+              <div className="space-y-2">
+                {blockedTasks.map((task) => (
+                  <TaskCard
+                    key={task.id}
+                    task={task}
+                    onStatusChange={handleStatusChange}
+                    onClick={() => setSelectedTask(task.id)}
+                    projectName={task.projectId ? projectMap[task.projectId] : undefined}
+                  />
+                ))}
+              </div>
+            </section>
+          )}
+
+          {/* Queue */}
+          {showSection("queued") && (
+            <section>
+              <h2 className="text-sm font-semibold text-gray-500 uppercase tracking-wide mb-3">
+                📋 Queue ({queuedTasks.length})
+              </h2>
+              {queuedTasks.length === 0 ? (
+                <div className="border-2 border-dashed border-gray-200 rounded-lg p-6 text-center text-gray-400">
+                  Queue is empty
+                </div>
+              ) : (
+                <div className="space-y-2">
+                  {queuedTasks.map((task, i) => (
+                    <TaskCard
+                      key={task.id}
+                      task={task}
+                      onStatusChange={handleStatusChange}
+                      onMoveUp={() => handleMoveUp(i)}
+                      onMoveDown={() => handleMoveDown(i)}
+                      isFirst={i === 0}
+                      isLast={i === queuedTasks.length - 1}
+                      onClick={() => setSelectedTask(task.id)}
+                      projectName={task.projectId ? projectMap[task.projectId] : undefined}
+                    />
+                  ))}
+                </div>
+              )}
+            </section>
+          )}
+
+          {/* Completed */}
+          {(showSection("completed") || showSection("cancelled")) && (
+            <section>
+              {filterStatus ? (
+                <>
+                  <h2 className="text-sm font-semibold text-gray-500 uppercase tracking-wide mb-3">
+                    {filterStatus === "completed" ? "✅" : "❌"} {filterStatus.charAt(0).toUpperCase() + filterStatus.slice(1)} ({completedTasks.length})
+                  </h2>
                   <div className="space-y-2 opacity-60">
                     {completedTasks.map((task) => (
                       <TaskCard
@@ -342,12 +369,34 @@ export function QueuePage() {
                       />
                     ))}
                   </div>
-                )}
-              </>
-            )}
-          </section>
-        )}
-      </div>
+                </>
+              ) : (
+                <>
+                  <button
+                    onClick={() => setShowCompleted(!showCompleted)}
+                    className="text-sm font-semibold text-gray-500 uppercase tracking-wide mb-3 flex items-center gap-1 hover:text-gray-700"
+                  >
+                    {showCompleted ? "▾" : "▸"} Completed / Cancelled ({completedTasks.length})
+                  </button>
+                  {showCompleted && (
+                    <div className="space-y-2 opacity-60">
+                      {completedTasks.map((task) => (
+                        <TaskCard
+                          key={task.id}
+                          task={task}
+                          onStatusChange={handleStatusChange}
+                          onClick={() => setSelectedTask(task.id)}
+                          projectName={task.projectId ? projectMap[task.projectId] : undefined}
+                        />
+                      ))}
+                    </div>
+                  )}
+                </>
+              )}
+            </section>
+          )}
+        </div>
+      )}
 
       {/* Task Detail Panel */}
       {selectedTaskData && (