M5: audio cache, style map, router (native non-verbal folding), ElevenLabs adapter with tests; speed test bypasses cache

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Mrituanjay Nath Jhayesterday

Co-Authored-By: Claude Sonnet 5.5 noreply@anthropic.com Entire-Checkpoint: 01M66A1P7C24EKV45QWQQPVYJR