[Task](ui): document Inline Action Box pattern

[franzheidl]

Task Description

The Inline Action Box is a UI pattern for situations where a contextual notice or condition needs to offer the user one or two follow-up actions — in place, without interrupting the current flow with a Modal. The pattern is built on the Box component.

The pattern has been specified in the UX docs (docs/ux/box.md).

Example

An example of the pattern. Note this is a specific/custom variant, this issue requires using standard Message variants only.

Sub-tasks

• Describe the pattern in the uxdocs (docs/ux/box.md, Inline Action Box section)
• Implement title prop on Box
• Add stories for the Inline Action Box pattern