Resolve Metaflow-uv TODO in model/flows/training_pipeline.py

[hanneshapke]

model/flows/training_pipeline.py:50 has a dangling TODO:

```python

TODO (Eddie): Update/remove this after feature support for ...

```

It's been there for a while and the context ("after feature support for [Metaflow + uv]") isn't fully captured in the comment, so anyone touching the file has to dig to figure out what's blocking the cleanup.

What to do

One of:

1. If the upstream feature has landed: remove the workaround and the TODO.
2. If it hasn't: rewrite the comment to be self-contained — link the upstream issue/PR being tracked, explain what the workaround is doing, and what the cleanup will look like. Optionally open a follow-up GitHub issue and replace the inline TODO with a link to it.

Hints

• Search the file around line 50 to understand what code the TODO guards.
• Check Metaflow / uv release notes since this was added.

Difficulty: good first issue, ~30 min.