feat(geschichte-detail): avatar metabar + doc reference cards per spec R-2/LR-2

Detail header gains the author avatar with a two-line author block;
journeys say 'zusammengestellt am' instead of 'veröffentlicht am'.
Bearbeiten/Löschen move into the metabar for stories too (were at the
article bottom). StoryReader renders real document reference cards
(icon, title, date · von X an Y) instead of a placeholder link, person
chips get avatar initials, and journey items lose the doubled spacing.
Shared formatDocumentMetaLine() in geschichte/utils feeds both readers.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

frontend/messages/en.json

@@ -1042,6 +1042,7 @@
 	"geschichten_empty_no_filter": "There are no published stories yet.",
 	"geschichten_back_to_index": "Back to stories",
 	"geschichten_published_on": "published on {date}",
+	"journey_compiled_on": "compiled on {date}",
 	"geschichten_persons_section": "People in this story",
 	"geschichten_documents_section": "Referenced documents",
 	"geschichten_document_link_placeholder": "Open document",