DataValue::LogLiteral and IngestedLine now carry an Arc<str> instead of an owned String, so the two clones the ingest path paid per line (once to move text into the write closure, once to store it) become cheap refcount bumps instead of full string copies. Also cuts the per-string-content cost of left_right's full-EngineSnapshot deep clone on each reconciliation sync. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01TeyhRfMYjMditek6geDRoQ