OpenRouter free models are removed from catalog instead of marking it as deprecated

[slmnsh]

Openrouter frequently updates their free models list. Currently the automatic script is removing the model entries immediately without any grace period.

It should mark the entries as deprecated instead of removing it instantly and remove later after 7/14 days grace period so users can migrate.

[github-actions]

This issue is not an actionable model catalog data fix. It requests a change to the automatic sync workflow's behavior — adding a grace period where removed OpenRouter free models are marked deprecated before being deleted — rather than correcting specific model/provider metadata or adding a missing model entry.

This is a policy/workflow change that needs maintainer review, and no automated fix was opened.