"""Embedding + vector storage (§4.3).

Embed DISTILLED PROPOSITIONS (not raw chunks) into a Qdrant HYBRID collection: dense bge-m3
(via the gateway) + BM25 sparse (client-side), so entity-heavy propositions (MSTR/Strategy/
Microstrategy) match on the lexical leg too. Retrieval goes through the gateway's /api/search.
"""