OptimalService.search / query (via _aggregate_citations) ran each index's
plugin.search() sequentially, and every plugin.search re-ran HyDE + embed — so an
N-index query made N LLM+embed round-trips in series (~28s across all indexes,
even though the SQL is fast). Embed the query ONCE
(BaseIndexPlugin.compute_query_embedding) and run every index's vector search
concurrently against that single embedding (search_with_embedding +
asyncio.gather). The search/query signatures and return contract are unchanged;
behavior is identical, just ~Nx fewer embed calls and parallel fetch.
Adds a regression test asserting one embed + per-index fan-out.
Renn F
d7aee91b39