Custom model

### Is there an existing issue for the same feature request?

- [x] I have checked the existing issues.

### Is your feature request related to a problem?

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### Describe the feature you'd like

Hope to be able to add addresses and models customarily. The default models are incomplete. Like Dify and FastGPT.

### Describe implementation you've considered

_No response_

### Documentation, adoption, use case

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### Additional information

_No response_

The issue does not name any files, tests, or entry points. First clarify what “addresses” and “custom models” mean, using Dify and FastGPT as reference points, then locate the model-configuration and integration areas. Done criteria are not specified and need agreement before implementation.

Written by the indexing model from the issue text.