Augment from DB · Phase 5 — stream-scan mode: scan a pulse stream, badge the already-known, one-click the new into the corpus

Step 8 lands as a mode of search-and-add, not a third remote (spec D3): a per-stream Scan button on the org card fires the existing official-blog machinery with the stream URL as the authoritative index, dedups against content_items, and the results rail badges what the corpus already holds.