[feat]. Add @codex -h help summary command

tests/test_commands.py

@@ -39,3 +39,16 @@ def test_parse_review_command_for_custom_alias() -> None:
     assert cmd is not None
     assert cmd.name == "review"
     assert cmd.mode == "tests"
+
+
+def test_parse_help_short_flag() -> None:
+    cmd = parse_command("@codex -h")
+    assert cmd is not None
+    assert cmd.name == "help"
+
+
+def test_parse_help_long_flag_and_arguments() -> None:
+    cmd = parse_command("@codex --help status quick", aliases={"codex"})
+    assert cmd is not None
+    assert cmd.name == "help"
+    assert cmd.arguments == ["status", "quick"]