[feat] Add support for tag selection (Using AI or Stats)

The Karakeep firefox extension allows for you to add a connection to an AI inference engine that helps you classify the tags on the article. This works pretty well, and you can even add explicit model selection.

I would love to see this support int he firefox extension here as well.

See: https://github.com/karakeep-app/karakeep/tree/main/apps/browser-extension for their implementation.

Another suggestion is potentially searching through the tags available to add based on the words in the archived page.

Start by reviewing the referenced Karakeep browser-extension implementation and then locate the corresponding tag and article-handling entry points in wallabagger. Clarify whether the feature should use an AI inference engine, tag-word matching, or both; done means the Firefox extension can select suitable tags using the agreed approach.

Written by the indexing model from the issue text.