v0.4.0: local reranking, 83 models

- add Infinity reranking service (michaelf34/infinity:0.0.77-cpu)
- mxbai-rerank-xsmall-v1 cross-encoder for RAG pipelines (~70MB, ONNX)
- local-infinity-rerank model routed via LiteLLM
- resource limits in recommend-limits.sh
- 83 models across 12 providers