Allow 'leann ask' to accept a positional question

tests/test_cli_ask.py

@@ -0,0 +1,14 @@
+from leann.cli import LeannCLI
+
+
+def test_cli_ask_accepts_positional_query(tmp_path, monkeypatch):
+    monkeypatch.chdir(tmp_path)
+
+    cli = LeannCLI()
+    parser = cli.create_parser()
+
+    args = parser.parse_args(["ask", "my-docs", "Where are prompts configured?"])
+
+    assert args.command == "ask"
+    assert args.index_name == "my-docs"
+    assert args.query == "Where are prompts configured?"