You are building a Dataflow streaming pipeline that reads clickstream events from Pub/Sub and enriches each event with product metadata (name, category, price). The product metadata is stored in a BigQuery table that is updated roughly once per hour and contains about 50,000 rows. You want the enrichment to reflect metadata updates without redeploying the pipeline, while keeping per-event latency low and avoiding a lookup call for every event. What is the best approach?