Update SKILL.md to reflect service.model.base_url changes

Now that service.model.base_url points to service.url + /v1 for
openai-format models, it is no longer deprecated and can be recommended
as the model endpoint.

Co-authored-by: Cursor <cursoragent@cursor.com>

Author: peterschmidt85

skills/dstack/SKILL.md

@@ -222,7 +222,7 @@ resources:
 - Without gateway: `<dstack server URL>/proxy/services/f/<run name>/`
 - With gateway: `https://<run name>.<gateway domain>/`
 - Authentication: Unless `auth` is `false`, include `Authorization: Bearer <DSTACK_TOKEN>` on all service requests.
-- OpenAI-compatible models: Use `service.url` from `dstack run get <run name> --json` and append `/v1` as the base URL; do **not** use deprecated `service.model.base_url` for requests.
+- Model endpoint: If `model` is set, `service.model.base_url` from `dstack run get <run name> --json` provides the model endpoint. For OpenAI-compatible models (default when `model` is a string), this will be `<dstack server URL>/proxy/services/<project>/<run name>/v1` (no gateway) or `https://<run name>.<gateway domain>/v1` (with gateway).
 - Example (with gateway):
   ```bash
   curl -sS -X POST "https://<run name>.<gateway domain>/v1/chat/completions" \