Delete explain.py

explain.py

@@ -1,12 +0,0 @@
-def explain(results):
-    return {
-        "total_results": len(results),
-        "sources": list(set(r.get("source") for r in results)),
-        "methods": [
-            "Public FOIA reading room search",
-            "Async fan-out querying",
-            "Deduplication",
-            "Semantic refinement (FAISS)"
-        ],
-        "no_restricted_access": True
-    }