AbstractCore v2.15.2

The default MLX model now names a repo that exists, so a first MLX download works, and
llms-full.txt covers every page the docs index links.

Fixed

• The default MLX model is now mlx-community/Qwen3-4B-4bit, a repo that exists on Hugging Face.
  create_llm("mlx") without a model and abstractcore-endpoint without --model asked for
  mlx-community/Qwen3-4B, which does not exist, so the first download failed. Examples in the
  package READMEs use the same id.

Documentation

• llms-full.txt now includes every page the docs index links, including Web and Document Tools,
  Prompt Caching, Hugging Face Model Compatibility, Fallbacks, Memory and Model Residency, Reasoning
  Control and the CLI app guides, which it left out before. The page list comes from docs/README.md,
  and a docs page the index does not link fails the check.