Add RealToBinary golang binding

[CascadingRadium]

• Add a go binding for the faiss_real_to_binary API that binarizes a batch of n * d input vector table in LSB format.
• Requires: Add C API to binarize vectors faiss#85

[Copilot]

Pull request overview

This PR adds a Go binding for the Faiss C API faiss_real_to_binary, enabling conversion of a batch of real-valued vectors (n*d float32 table) into packed binary vectors (LSB bit packing), which is useful for interacting with Faiss binary/vector-quantization workflows.

Changes:

• Add the missing Faiss C header include needed for the faiss_real_to_binary symbol.
• Introduce RealToBinary(x []float32, d int) []uint8 helper to binarize vectors into n*(d/8) bytes.

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