v0.3.0

Release v0.3.0\n\n- Preserve EPUB paragraph boundaries instead of merging paragraphs together.\n- Add natural audiobook pacing defaults: speed=0.9, paragraph pauses, and dialogue pauses.\n- Split quoted dialogue into separate expressive audio segments.\n- Add dialogue_exaggeration and dialogue_cfg_weight controls.\n- Adjust M4B chapter metadata for tempo changes.\n- Raise GenerationError with chapter title and text preview when TTS generation fails.