Patterns: iterate on experience of registering patterns from pattern directory for themers

[annezazu]

With block themes increasing and patterns continuing to play an important role, I want to return to the efforts to allow for patterns to be registered from the pattern directory via theme.json in #38323.

In that PR, a discussion was had around categories since there is no parity between pattern directory categories and core categories. Without going into iterating on pattern categories #47847, I wanted to open an issue around the experience of registering patterns from the pattern directory for themes, how we can filter those patterns, and the expected experience for categorizing these patterns. A few points:

• When filtering, patterns are shown as provided by the directory rather than the theme.
• Patterns that don't match core categories are marked as uncategorized with no way to adjust that resulting in a poor experience.
• Patterns aren't visible in the Patterns section of the Site Editor, like you'd expect with other theme patterns.

Here's a quick video showing some of this:

pattern.experience.register.themejson.mov

Ideally, theme authors could use the pattern directory as a main way to reference patterns (which would benefit the larger ecosystem with more patterns to pull from) and even reuse across different themes if they wanted. Before doing this though, these kinks needed to be sorted out, particularly with controlling categorization and filtering. Is there a way we could auto add a category or register a new category for patterns registered for a theme in this way? This was briefly discussed in the original PR #38323 (comment)

This also touches on this broader issue of having a "theme source" for patterns in the pattern directory which I could imagine would make the experience more tightly coupled and clear WordPress/pattern-directory#573

cc @WordPress/block-themers for more insights and feedback :)

[richtabor]

Is there a way we could auto add a category or register a new category for patterns registered for a theme in this way? This was briefly discussed in the original PR #38323 (comment)

Just to confirm, this is for when a pattern from the WordPress Patterns directory is in a category that is not locally available on the site, right?