Checkpoint
One last thing before we move on. Same surface as a write step — but the lesson doesn't complete until this passes.
Build the idempotent half of resume: write ingest(start_page) that pages until empty and upserts every record into the store dict KEYED BY r["id"]. Then run ingest(1) twice — a resume that redoes work — and prove the store still has exactly 3 unique records.