[model] support Qwen/Qwen3.6-27B

[Jintao-Huang]

No description provided.

[gemini-code-assist]

Code Review

This pull request adds support for the Qwen3.6-27B and Qwen3.6-27B-FP8 models by updating the documentation and the model registry in swift/model/models/qwen.py. Feedback was provided regarding the formatting of the new model group to ensure consistency with the existing code style and a suggestion to merge the new models into the existing Qwen3.5 group to reduce redundancy.

[gemini-code-assist]

The indentation and formatting of the new ModelGroup do not match the existing style in this file (see lines 1473-1478). For consistency, please use 8-space indentation for the Model items and place the TemplateType on a new line. Additionally, since these models use the same TemplateType.qwen3_5 as the previous group, they could be merged into a single ModelGroup to reduce redundancy and maintain a cleaner model list.

            ModelGroup([
                    Model('Qwen/Qwen3.6-27B', 'Qwen/Qwen3.6-27B'),
                    Model('Qwen/Qwen3.6-27B-FP8', 'Qwen/Qwen3.6-27B-FP8'),
                ],
                TemplateType.qwen3_5),