gguf code codeqwen chat qwen qwen-coder quantized GGUF quantization imat imatrix static 16bit 8bit 6bit 5bit 4bit 3bit 2bit 1bit text-generation en base_model:Qwen/Qwen2.5-Coder-7B-Instruct base_model:quantized:Qwen/Qwen2.5-Coder-7B-Instruct license:apache-2.0 region:us conversational