Update README: arXiv link, baseline results from paper

Rename 'emotional' split to 'expressive'

Move title above logo image

Replace badge links with text links

Add Tech Report / Code / Model / 1B badge row

Add copyright notice

Unify citation; update tags

Rename Raon-TTS-Eval to Raon-OpenTTS-Eval; add configs for dataset viewer splits

README already reflects AMI-SDM replacing Switchboard (no change needed)

Add YAML frontmatter

Rename RAON-TTS to Raon-OpenTTS throughout README

initial commit