feat(HAI-002): create WorktreeGroup component

packages/dashboard/app/components/WorktreeGroup.tsx

@@ -0,0 +1,42 @@
+import type { Task, TaskDetail } from "@hai/core";
+import { TaskCard } from "./TaskCard";
+import type { ToastType } from "../hooks/useToast";
+
+interface WorktreeGroupProps {
+  label: string;
+  activeTasks: Task[];
+  queuedTasks: Task[];
+  onOpenDetail: (task: TaskDetail) => void;
+  addToast: (message: string, type?: ToastType) => void;
+}
+
+export function WorktreeGroup({
+  label,
+  activeTasks,
+  queuedTasks,
+  onOpenDetail,
+  addToast,
+}: WorktreeGroupProps) {
+  return (
+    <div className="worktree-group">
+      <div className="worktree-group-header">
+        <span className="worktree-icon">
+          {label === "Up Next" || label === "Unassigned" ? "📋" : "🌿"}
+        </span>
+        <span className="worktree-label">{label}</span>
+      </div>
+      {activeTasks.map((task) => (
+        <TaskCard key={task.id} task={task} onOpenDetail={onOpenDetail} addToast={addToast} />
+      ))}
+      {queuedTasks.map((task) => (
+        <TaskCard
+          key={task.id}
+          task={task}
+          queued
+          onOpenDetail={onOpenDetail}
+          addToast={addToast}
+        />
+      ))}
+    </div>
+  );
+}