feat: public API, SEO and existing surfaces

features/media_field_library.qa.md

@@ -20,7 +20,7 @@ Decisions accepted by the user (all as the feature draft assumes):
 - D4 truncation: one line, ellipsis, native title.
 - D5 usage failure: inline message with "Try again" in the panel, silent tooltip.
 - D6 usage loading: skeleton after 150 ms, delete dialog opens at once with a generic description.
-- D7 authors and sites in the usage: filtered out, heading counts articles only.
+- D7 authors and sites in the usage: filtered out, heading counts articles only. Article items carry `story_id` and `lang`; articles are grouped by `story_id` (a story counts once, in the heading, the panel and the delete dialog); items without `story_id` still render one row each. See features/localization_public_api_and_surfaces.qa.md, item 8 of the SPA list.
 - D8 bulk delete: "N places".
 - D9 merge: "N places".
 - D10 entry rows in the delete dialog are not links.