feat: MLOps eval, A/B testing, DLQ, WebSocket, cold-start fallback

fix: API quality fixes (await redis, Kafka lifecycle, Prometheus dedup, lifespan)

feat: FastAPI service with Redis/Postgres/ALS fallback chain and Prometheus metrics

fix: streaming job quality fixes (pg reconnect, watermark docs, edge cases)

feat: Spark Structured Streaming with time-decay re-ranking (foreachBatch)

fix: bootstrap quality fixes (unused param, sim clip, stronger tests)

feat: ALS bootstrap with item similarity and Redis/Postgres seeding

fix: uv workspace project table, workspace deps in tests, kafka-python-ng

chore: repo scaffolding, uv workspace, project structure