feat(v2): add snapshot extractor framework and run command

apps/ingestion/extractors/registry.py

@@ -0,0 +1,22 @@
+from __future__ import annotations
+
+from .base import BaseSnapshotExtractor, ExtractorConfigError
+from .public_json import PublicJsonSnapshotExtractor
+
+EXTRACTOR_REGISTRY: dict[str, type[BaseSnapshotExtractor]] = {
+    PublicJsonSnapshotExtractor.extractor_name: PublicJsonSnapshotExtractor,
+}
+
+
+def available_extractors() -> list[str]:
+    return sorted(EXTRACTOR_REGISTRY.keys())
+
+
+def create_extractor(extractor_name: str) -> BaseSnapshotExtractor:
+    try:
+        extractor_cls = EXTRACTOR_REGISTRY[extractor_name]
+    except KeyError as exc:
+        raise ExtractorConfigError(
+            f"Unknown extractor '{extractor_name}'. Available: {', '.join(available_extractors())}"
+        ) from exc
+    return extractor_cls()