feat(components): implement segment specific breadcrumbs - #8459

📄 Description

This PR adds a show-home-text prop to <post-breadcrumbs>. When true, it shows text-home as visible text instead of the home icon, so the root segment can link to a segment's own home page instead of the generic site root (e.g. "Private customers").

Degrade behavior

Home and the last (selected) segment never truncate. As per design, when space runs out:

1. Middle items collapse into the overflow menu first
2. Home collapses into its own menu next
3. Only as a last resort does the last item wrap onto multiple lines

This PR also adds a text-expand-home prop. It's required only once home actually collapses into its own menu, and it's used as the accessible label for its trigger.

Docs

This PR improves the breadcrumbs docs to make them more user friendly and easier to find. It introduces a layout with tabs for the examples section (similar concept that is used in the Self managed header page).

Tests

There were no e2e tests for post-breadcrumbs before this PR. Since the concatenation logic was recently improved, I also added test coverage for it to make sure no one breaks it later on, alongside tests for the new segment specific breadcrumbs behavior.

🚀 Demo

🔮 Design review

• Design review done
• No design review needed

🧪 Visual regression tests

• Visual changes detected and approved (Check this box if VRT fails and changes are intentional)

📝 Checklist

• ✅ My code follows the style guidelines of this project
• 🛠️ I have performed a self-review of my own code
• 📄 I have made corresponding changes to the documentation
• ⚠️ My changes generate no new warnings or errors
• 🧪 I have added tests that prove my fix is effective or that my feature works
• ✔️ New and existing unit tests pass locally with my changes