[6.x] Entry parent badge for listing view

[jaygeorge]

Description of the Problem

In structured collections, entries with the same title (e.g. two “Tomato” pages under different parents) are indistinguishable in List mode — Entries/Link browsers, Bard link picker, Nav “Link to Entry”, and the collection listing. With multiple collections configured, Tree mode isn’t available, so there’s no hierarchy cue at all. Closes #15598.

What this PR Does

• Adds structure parent breadcrumbs (nearest parent first; collection root omitted when expectsRoot)
• Shows them as a pill badge with chevron separators next to the title in the collection listing and relationship selector
• Includes the breadcrumb in Entries fieldtype item hints (before collection/site)
• Exposes breadcrumbs as an array from the listing API so titles containing ‹/› don’t break

How to Reproduce

1. Use a structured Pages collection with the same title under different parents (e.g. Fruit → Tomato, Vegetables → Tomato), optionally nest deeper (Vegetables → Tomato → Love Actually)
2. Open Collections → Pages → List — each ambiguous title should show its parent path (e.g. ‹ Fruit, ‹ Tomato ‹ Vegetables)
3. On an Entries/Link field (especially multi-collection so Tree is unavailable), open the browser in List mode — same badges, and select/typeahead hints include the path

[jasonvarga]

Hold off on this for a moment. Something like this was already being introduced in #15192.