feat: add task list pagination

tests/test_mvp_backend.py

@@ -121,6 +121,55 @@ def test_tasks_can_be_loaded_by_list_and_completion_filter(client):
     assert [item["title"] for item in response.json()["items"]] == ["收集箱未完成"]
 
 
+def test_tasks_support_numbered_pagination_with_total(client):
+    inbox = boot(client)
+    for index in range(5):
+        client.post("/api/v1/tasks", json={"title": f"任务 {index}", "list_id": inbox["id"]})
+
+    first = client.get("/api/v1/tasks", params={"list_id": inbox["id"], "page": 1, "page_size": 2})
+    second = client.get("/api/v1/tasks", params={"list_id": inbox["id"], "page": 2, "page_size": 2})
+
+    assert first.status_code == 200
+    assert first.json()["total"] == 5
+    assert first.json()["page"] == 1
+    assert first.json()["page_size"] == 2
+    assert len(first.json()["items"]) == 2
+    assert len(second.json()["items"]) == 2
+    assert {item["id"] for item in first.json()["items"]}.isdisjoint(
+        {item["id"] for item in second.json()["items"]}
+    )
+
+
+def test_tasks_support_due_range_pagination(client):
+    inbox = boot(client)
+    client.post("/api/v1/tasks", json={"title": "今天", "list_id": inbox["id"], "due_at": "2026-09-05T08:00:00Z"})
+    client.post("/api/v1/tasks", json={"title": "以后", "list_id": inbox["id"], "due_at": "2026-09-08T08:00:00Z"})
+    client.post("/api/v1/tasks", json={"title": "无日期", "list_id": inbox["id"]})
+
+    response = client.get(
+        "/api/v1/tasks",
+        params={"due_from": "2026-09-05T00:00:00Z", "due_to": "2026-09-06T00:00:00Z", "page": 1},
+    )
+
+    assert response.status_code == 200
+    assert response.json()["total"] == 1
+    assert [item["title"] for item in response.json()["items"]] == ["今天"]
+
+
+def test_trash_supports_numbered_pagination_with_total(client):
+    inbox = boot(client)
+    for index in range(3):
+        task = client.post("/api/v1/tasks", json={"title": f"删除 {index}", "list_id": inbox["id"]}).json()
+        client.delete(f"/api/v1/tasks/{task['id']}")
+
+    response = client.get("/api/v1/trash", params={"page": 2, "page_size": 2})
+
+    assert response.status_code == 200
+    assert response.json()["total"] == 3
+    assert response.json()["page"] == 2
+    assert len(response.json()["items"]) == 1
+
+
 def test_ticktick_preview_import_dedupe_and_json_restore(client):
     boot(client)
     csv_data = "Title,List Name,Due Date,Status,ID\nImported,Inbox,2026-10-01,0,ext-1\n"