bug: Moonshot models deprecated

- [x] I have looked for existing issues (including closed) about this

## Bug Report

When using provider `moonshot` 's model kimi K2.5
``` rust
let agent = moonshot
.agent(moonshot::KIMI_K2_5)
.build();
```
report following error:
`CompletionError: HttpError: Invalid status code 404 Not Found with message: {"error":{"message":"Not found the model kimi-k2.5 or Permission denied","type":"resource_not_found_error"}}`

In the [rig 0.42.0 document](https://docs.rs/rig/0.42.0/rig/providers/moonshot/) there are `KIMI_K2` and `KIMI_K2_5` However the official kimi api website [kimi api](https://platform.kimi.com/docs/models) shows that both k2 and k2.5 have been taken offline (deprecated). Current available models are `kimi-k3`, `kimi-k2.7-code`, `kimi-k2.7-code-highspeed` and `kimi-k2.6`

## Reproduction

When using provider `moonshot` 's model kimi K2.5
``` rust
let agent = moonshot
.agent(moonshot::KIMI_K2_5)
.build();
```

## Expected behavior

Support `kimi-k3`, `kimi-k2.7-code`, `kimi-k2.7-code-highspeed` and `kimi-k2.6`.

## Screenshots

## Additional context

Check the moonshot provider module in the rig codebase, likely under src/providers/moonshot.rs. Look for the model constants like KIMI_K2_5. Compare with the official Kimi API documentation to update the available model list. Add new constants for kimi-k3, kimi-k2.7-code, kimi-k2.7-code-highspeed, and kimi-k2.6, and mark the deprecated ones. Run any existing tests for the moonshot provider to ensure changes work.

Vom Indexierungsmodell aus dem Issue-Text verfasst.