docs: make native Transformers the Nano starting point

[LauraGPT]

Summary

• Make released Transformers 5.17.0 and the official native -hf export the first Python path in all four READMEs.
• Add an isolated CPU CLI, local audio/batches/keywords, a notebook, and model-free CI. Keep toolkit, native vLLM, GGUF and the 31-language MLT checkpoint separate.
• Keep release news concise and preserve existing examples and translated anchors.

Verification

• 21 local contract tests passed.
• Actual released-wheel CPU inference: fixed English URL, Chinese waveform, Chinese keywords, padded Chinese/English batch.
• Unmodified CLI default/batch/keywords and documented Python recipe passed; notebook Python cells executed with the configurable local input set to a public fixture. This is not a hosted Colab, GPU, accuracy or capacity claim.
• Signed commit with DCO; pre-push source, diff and SHA256 backups retained.

No weights or runtime implementation changed.