Semantic search by vector: the query text never reaches the server

Same ranking and the same memories as GET (both use one scoring function), but the client sends the query's vector in the body instead of its text. The server never sees the query and logs only that a vector search happened. Sealed matches come back with scheme: sealed, summary: null and their blob_b64, so the client decrypts them without another request. Since 2026-09-21.