feat(etl-cache): add ParseKey cache identity value object

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

@@ -0,0 +1,28 @@
+"""Identity of a cacheable parse: equal keys yield identical markdown."""
+
+from __future__ import annotations
+
+from dataclasses import dataclass
+
+
+@dataclass(frozen=True, slots=True)
+class ParseKey:
+    source_sha256: str
+    etl_service: str
+    mode: str
+    version: int
+
+    @classmethod
+    def for_document(
+        cls, source_sha256: str, *, etl_service: str, mode: str, version: int
+    ) -> "ParseKey":
+        return cls(
+            source_sha256=source_sha256,
+            etl_service=etl_service,
+            mode=mode,
+            version=version,
+        )
+
+    @property
+    def object_suffix(self) -> str:
+        return f"{self.etl_service}.{self.mode}.v{self.version}.md"