fix(test): tighten parameterized_cases validation

Set generated parameterized class metadata for clearer unittest output, reject
empty parameterized_cases inputs explicitly, and keep the curated descriptor
cases aligned with review feedback.

Authored by OpenClaw (model: gpt-5.4)

Author: njzjz-bot

source/tests/consistent/common.py

@@ -778,6 +778,8 @@ def parameterized_cases(*cases: tuple) -> Callable:
     object
         The decorator.
     """
+    if not cases:
+        raise ValueError("parameterized_cases requires at least one case tuple")
     return _parameterized_with_cases(list(cases))