* server : use pytest-xdist for server tests
This commit adds pytest-xdist to the server tests. This is pytest
plugin that distributes test execution across multiple CPU cores.
Assisted-by: pi:llama.cpp/qwen3.8-27B
Refs: https://github.com/ggml-org/llama.cpp/pull/26734#issuecomment-5220707042
* remove server_base_port and BASE_PORT
* use worksteal and pytest builting tmp_path
* server : add Anthropic Messages API support
* remove -@pytest.mark.slow from tool calling/jinja tests
* server : remove unused code and slow/skip on test_anthropic_vision_base64_with_multimodal_model in test_anthropic_api.py
* server : removed redundant n field logic in anthropic_params_from_json
* server : use single error object instead of error_array in streaming response handler for /v1/chat/completions and use unordered_set instead of set in to_json_anthropic_stream()
* server : refactor Anthropic API to use OAI conversion
* make sure basic test always go first
* clean up
* clean up api key check, add test
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Co-authored-by: Xuan Son Nguyen <son@huggingface.co>