docs: add model publishing instructions to the Docker Model Runner docs (#22819)

## Description

- Introduced a new section on publishing models, including tagging and
pushing to Docker Hub.
- Added examples for tagging existing models and packaging GGUF format
models as OCI Artifacts.
- Clarified that the functionality supports any Container Registry
compatible with OCI Artifacts.

---------

Co-authored-by: Allie Sadler <[email protected]>
Co-authored-by: aevesdocker <[email protected]>

Author: kiview

content/manuals/ai/model-runner/_index.md

@@ -129,6 +129,36 @@ Use the [`docker model log` command](/reference/cli/docker/).
 {{< /tab >}}
 {{< /tabs >}}
 
+## Publish a model
+
+> [!NOTE]
+>
+> This works for any Container Registry supporting OCI Artifacts, not only Docker Hub.
+
+You can tag existing models with a new name and publish them under a different namespace and repository:
+
+```console
+# Tag a pulled model under a new name
+$ docker model tag ai/smollm2 myorg/smollm2
+
+# Push it to Docker Hub
+$ docker model push myorg/smollm2
+```
+
+For more details, see the [`docker model tag`](/reference/cli/docker/model/tag) and [`docker model push`](/reference/cli/docker/model/push) command documentation.
+
+You can also directly package a model file in GGUF format as an OCI Artifact and publish it to Docker Hub.
+
+```console
+# Download a model file in GGUF format, e.g. from HuggingFace
+$ curl -L -o model.gguf https://huggingface.co/TheBloke/Mistral-7B-v0.1-GGUF/resolve/main/mistral-7b-v0.1.Q4_K_M.gguf
+
+# Package it as OCI Artifact and push it to Docker Hub
+$ docker model package --gguf "$(pwd)/model.gguf" --push myorg/mistral-7b-v0.1:Q4_K_M
+```
+
+For more details, see the [`docker model package`](/reference/cli/docker/model/package/) command documentation.
+
 ## Example: Integrate Docker Model Runner into your software development lifecycle
 
 You can now start building your Generative AI application powered by the Docker Model Runner.