Allow updating library on a single app.

[stavros-k]

Currently, when running the hash generate it does so for all apps.
And if all the apps has the "latest" library set, it will take ~15-20s to complete.
But doing this for only a single app takes <2s.

This helps a lot when doing local dev or CI, as the lib update is part of the CI script I run to render the app.

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Also cleans up older libraries, as we only use a single version per app.

[Copilot]

Pull request overview

This PR adds the ability to update the library on a single app instead of updating all apps in the catalog. It introduces optional --train and --app command-line arguments that must be specified together to target a specific app.

Key changes:

• Added train_name and app_name parameters to the update_catalog_hashes function with validation requiring both to be specified together
• Implemented filtering logic to process only the specified app when single-app mode is active
• Changed library cleanup behavior to remove all old library versions instead of just the target version

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[Copilot]

Pull request overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated 5 comments.

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[Copilot]

Pull request overview

Copilot reviewed 1 out of 1 changed files in this pull request and generated 3 comments.

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