Pipeline mode calls retrieve() three times (NREM, Early REM, Late REM).
Previously each call re-imported and re-instantiated SentenceTransformer
("all-MiniLM-L6-v2"), allocating ~200MB and spending 30-60s on disk->CPU
init three times sequentially. lru_cache(maxsize=1) makes the load happen
once per process.
Expected: pipeline runtime drops ~100-180s, removes 2x redundant 200MB
allocations, and reduces transient memory pressure during the same window
when other nightly jobs may run.
aaron
b35d44ef58