GitLab

- Any engine can take the name of a Hugging Face repository. It will be downloaded before calling the engine.

- The default engine (previously always mistralrs) depends on what is compiled in.

- Text can be piped in and will result in a single run of the model.

All of those together mean if you build with `--features vllm` you can do this and it will download the model and run it with vllm, answer your question, and exit:
```
echo "What is the capital of Costa Rica?"  | dynamo-run Qwen/Qwen2.5-3B-Instruct
```
Co-authored-by: Ryan McCormick <rmccormick@nvidia.com>

Co-authored-by: Harrison King Saturley-Hall <hsaturleyhal@nvidia.com>

Co-authored-by: Biswa Panda <biswa.panda@gmail.com>

There are two etcd keys:
- The service
- The model

The second one is the interesting one for us. Previously we confused the two.

Replaces hard-coded "kv-hit-rate" string in multiple places with KV_HIT_RATE_SUBJECT constant in lib/llm.

Co-authored-by: Graham King <grahamk@nvidia.com>

Co-authored-by: Ryan Olson <rolson@nvidia.com>

This means we don't need to explain the parts to the users until they are ready. We use what they provide and default the rest.

Allows all of this and more:
- `tio out=tdr://test`
- `tio out=tdr://llama_8b_pool`
- `tio in=tdr://corp_ai_research_group/model_next-20250226`
- `tio out=tdr://AIRE.NIM.migrate.mistralrs.1802`

Python, API, etc all untouched.

Co-authored-by: aflowers <aflowers@nvidia.com>

Signed-off-by: Neelay Shah <neelays@nvidia.com>
Co-authored-by: Ryan McCormick <rmccormick@nvidia.com>