feat(graders): add programmatic_grader scaffold and grade_episode() signature

graders/programmatic_grader.py

@@ -0,0 +1,9 @@
+"""
+Programmatic Grader — The Master Grader
+Orchestrates easy, medium, and hard components into a single report.
+"""
+from typing import Any
+
+def grade_episode(history: list[dict]) -> dict[str, Any]:
+    """Master grading function."""
+    return {}