feat: add application.yaml to configure api key

[Akika404]

In the current examples/simple_sandbox_tool_example, the default api includes the /api prefix, but it missing the resources/application.yaml, causing request errors in the example.

This PR adds the application.yaml file to configure the context-path and DASHSCOPE_API_KEY.

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[xuehuitian45]

Hello, the "/api" context path has already been added in controller in the newest PR #49. You can remove that. The other fields look good to me.

[Akika404]

Hello, the "/api" context path has already been added in controller in the newest PR #49. You can remove that. The other fields look good to me.

ok, I will remove it.