feat(etl-cache): expose cache schema value objects

surfsense_backend/app/etl_pipeline/cache/schemas/__init__.py

@@ -0,0 +1,11 @@
+"""Pure value objects for the parse cache."""
+
+from __future__ import annotations
+
+from .eviction_candidate import EvictionCandidate
+from .parse_key import ParseKey
+
+__all__ = [
+    "EvictionCandidate",
+    "ParseKey",
+]