v4.0.0 — Full MLX LLM stack

Summary LLM and vision OCR now run in-process via mlx-lm + mlx-vlm on Apple Silicon, unifying with CSM-1B TTS under one framework. Ollama removed — no external daemon needed.

What changed

• OllamaConfig → LLMConfig; config key ollama: → llm: (old key auto-migrated)
• ollama dependency replaced by mlx-lm + mlx-vlm
• +25–30% generation speed
• Model discovery scans HF cache instead of Ollama API
• Default model: mlx-community/Qwen3.5-9B-4bit