Fix model namespace normalization for locally packaged models

[Copilot]

Problem

When users packaged a local GGUF model without specifying a namespace, the model could not be run afterward. This occurred because the model name was not normalized during packaging, causing a mismatch between the stored name and the name used during lookup.

For example:

docker model package --gguf /path/to/output/gemma-3-270m-it.F16.gguf my-model
# Model loaded successfully

docker model list
# Shows: my-model (without ai/ prefix)

docker model run my-model
# Error: Failed to inspect model: invalid model name: my-model:latest

The root cause was that:

1. The package command stored the model without normalizing the name (e.g., as my-model)
2. The run command normalized my-model to ai/my-model:latest before lookup
3. The lookup failed because ai/my-model:latest didn't match the stored name

Solution

This PR ensures that model names are normalized to include the default ai/ namespace before being stored, making the behavior consistent across all operations. Now my-model becomes ai/my-model:latest during packaging, which matches what all other commands expect.

Changes

• cmd/cli/commands/package.go: Added model name normalization before creating tags in newModelRunnerTarget()
• cmd/cli/commands/tag.go: Added target model name normalization before creating tags in tagModel()
• cmd/cli/commands/utils_test.go: Added test to verify normalization consistency for locally packaged models

Result

The workflow now works seamlessly:

docker model package --gguf /path/to/model.gguf my-model
# Model is stored as: ai/my-model:latest

docker model list
# Shows: ai/my-model:latest

docker model run my-model
# Normalizes to ai/my-model:latest and runs successfully!

This ensures that ai/ is the default namespace in all cases, as intended by the original design.

Fixes issue where locally packaged models without explicit namespaces could not be run.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Bug related to running locally packaged/loaded model</issue_title>
<issue_description>I've recently fine-tuned a local model and packaged/loaded the GGUF model. That model name didn't have a namespace associated with it, as I had no intent of pushing the model. However, when attempting to run the model, it failed with an error indicating the model name was invalid (screenshot below).

cc @ericcurtin </issue_description>

<agent_instructions>"ai/" should be the default namespace in all cases.</agent_instructions>

Comments on the Issue (you are @copilot in this section)

Fixes docker#250

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