rfdb-batchhandle-deletes-existing-nodes

Fix nodes silently disappearing from RFDB when an enricher or post-resolution pass writes new nodes via BatchHandle. Use when: (1) writing a TypeScript enricher that should ADD nodes/edges to existing files, (2) after calling client.createBatch() + batch.addNode({file: 'X', ...}) + batch.commit() the original nodes in file X have vanished, (3) tests that load a graph fixture, run an enricher, then query original…