feat(250): add Active/Archived tab toggle to Plans page

app/(app)/plans/page.tsx

@@ -41,6 +41,7 @@ const emptyForm = {
 export default function PlansPage() {
   const qc = useQueryClient();
   const [search, setSearch] = useState("");
+  const [activeTab, setActiveTab] = useState<"active" | "archived">("active");
 
   // Modals
   const [showCreate, setShowCreate] = useState(false);
@@ -51,11 +52,12 @@ export default function PlansPage() {
   const [createForm, setCreateForm] = useState({ ...emptyForm });
   const [editForm, setEditForm] = useState({ ...emptyForm });
 
-  // GET /plans returns a plain array (not paginated)
+  // GET /plans with isActive filter
   const { data: allPlans = [], isLoading, isError, refetch } = useQuery<Plan[]>({
-    queryKey: ["plans"],
+    queryKey: ["plans", activeTab],
     queryFn: async () => {
-      const res = await api.get<Plan[] | { data: Plan[] }>("/api/v1/plans");
+      const isActive = activeTab === "active";
+      const res = await api.get<Plan[] | { data: Plan[] }>(`/api/v1/plans?isActive=${isActive}`);
       return Array.isArray(res.data) ? res.data : (res.data as any).data ?? [];
     },
   });
@@ -149,6 +151,24 @@ export default function PlansPage() {
         </div>
       </div>
 
+      {/* Active / Archived tabs */}
+      <div className="flex gap-1 bg-gray-100 rounded-lg p-1 w-fit">
+        <button
+          onClick={() => { setActiveTab("active"); setSearch(""); }}
+          className={`px-4 py-1.5 rounded-md text-sm font-medium transition-colors ${activeTab === "active" ? "bg-white text-gray-900 shadow-sm" : "text-gray-500 hover:text-gray-700"}`}
+          data-testid="tab-active"
+        >
+          Active
+        </button>
+        <button
+          onClick={() => { setActiveTab("archived"); setSearch(""); }}
+          className={`px-4 py-1.5 rounded-md text-sm font-medium transition-colors ${activeTab === "archived" ? "bg-white text-gray-900 shadow-sm" : "text-gray-500 hover:text-gray-700"}`}
+          data-testid="tab-archived"
+        >
+          Archived
+        </button>
+      </div>
+
       <Card>
         <CardHeader>
           <input