Indexes one page of live listings into the full-text search index.

Requires CARGA_TOKEN. Pages by rowid: apos is the last rowid already indexed, limite the page size (≤ 500). Each page reserves 5 write units per listing in the daily catalog budget before writing; 429 means try tomorrow. An empty page marks the index ready (fts:pronto) and the search switches from LIKE to the index. Returns: { ok, indexados, ultimo, pronto }