merge and lint

semantic_router/encoders/__init__.py

semantic_router/encoders/base.py

semantic_router/encoders/bm25.py

semantic_router/encoders/cohere.py

semantic_router/encoders/fastembed.py

semantic_router/encoders/huggingface.py

semantic_router/encoders/openai.py

semantic_router/hybrid_layer.py

semantic_router/layer.py

semantic_router/llms/base.py

semantic_router/llms/cohere.py

semantic_router/llms/openai.py

semantic_router/llms/openrouter.py

semantic_router/route.py

semantic_router/schema.py

semantic_router/utils/function_call.py

semantic_router/utils/splitters.py

tests/unit/test_hybrid_layer.py