The "Häufige Korrespondenten" card linked into the standalone Briefwechsel
view. Retarget each chip to the existing document search pre-filtered by
sender and receiver (/documents?senderId=A&receiverId=B), naming both
persons in a search-action title, swapping the chat-bubble icon for a
magnifier, and clarifying that the ×N badge counts shared letters in both
directions (not the unidirectional search result count).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>