feat(profile): add full-box card background tab and rendering

Adds a "Cards" tab to the Profile Background picker (BackgroundsView)
that selects a pattern applied to the entire user info card and the
extended profile container, in addition to the existing avatar-pad
background/stand/overlay layers.

- AvatarInfoUser/Utilities: propagate cardBackgroundId from RoomUserData.
- InfoStandWidgetUserView: stateful cardBackgroundId, applied as
  .profile-card-background.card-background-{id} on the outer Column
  with bg-color suppressed when active.
- UserContainerView: same class on the wrapper of the extended profile.
- BackgroundsView: 4th tab "cards" backed by cards.data config
  (falls back to backgrounds.data); sends 4-id message via the
  extended sendBackgroundMessage signature.
- ui-config.example: cards.data dataset (15 entries).
- BackgroundsView.css: 188 .card-background-{N} rules cloned from
  background-{N} (repeat-tiled) plus 15 CSS-pattern overrides for the
  provisional dataset (gradients, stripes, dots, grid, checker).

src/components/user-profile/UserContainerView.tsx

@@ -18,6 +18,7 @@ export const UserContainerView: FC<{
     const infostandBackgroundClass = `background-${userProfile.backgroundId ?? 'default'}`;
     const infostandStandClass = `stand-${userProfile.standId ?? 'default'}`;
     const infostandOverlayClass = `overlay-${userProfile.overlayId ?? 'default'}`;
+    const profileCardBgClass = userProfile.cardBackgroundId ? `card-background-${userProfile.cardBackgroundId}` : '';
 
     const addFriend = () =>
     {
@@ -32,7 +33,7 @@ export const UserContainerView: FC<{
     }, [ userProfile ]);
 
     return (
-        <div className="flex gap-2">
+        <div className={`flex gap-2 p-2 rounded profile-card-background ${profileCardBgClass}`}>
             <div className={`flex flex-col justify-center items-center w-[75px] h-[120px] rounded-sm relative overflow-hidden profile-background ${infostandBackgroundClass}`}>
                 <div className={`absolute inset-0 profile-stand ${infostandStandClass}`} />
                 <LayoutAvatarImageView direction={ 2 } figure={ userProfile.figure } />