agentsop-idempotent-ingestion

Re-ingest-correctness SOP for production RAG. Activate when a calling agent builds, reviews, or debugs an ingestion pipeline that runs more than once over a changing corpus — scheduled re-index, incremental updates, CI re-ingest, or a "retrieval has duplicates / shows deleted docs" bug. Encodes the rule — ingestion must be idempotent: a document's content hash decides insert/update/skip, so re-running over unchanged…