On a large tree the duplicate's other copy is usually off-screen, so flashing
in place wasn't enough. Clicking the ×N badge now pans/zooms the view to center
the other copy and flashes it on arrival; clicking again cycles through the
remaining copies (for a person drawn 3+ times).
Uses family-chart's exported handlers: cardToMiddle centers a datum (read from
the target card_cont's bound x/y, falling back to its transform attr), keeping
the current zoom level via getCurrentZoom. Verified against the lib: the svg's
parent (f3Canvas) holds the zoom object, and cards are positioned by datum x/y —
same coordinate space cardToMiddle expects. Falls back to an in-place flash if
the zoom object isn't ready. Frontend only; supersedes the flash-only behavior.
Signed-off-by: Justin Paul <justin@jpaul.me>
justin