feat(falukant): add child portrait backdrops

frontend/src/views/falukant/FamilyView.vue

@@ -334,7 +334,11 @@
                                                 class="character-avatar character-avatar--compact"
                                                 :style="getCharacterAvatarStyle(child, 0.5)"
                                             ></div>
-                                            <div v-if="showCharacterFigure3d" class="character-3d-frame character-3d-frame--compact">
+                                            <div
+                                                v-if="showCharacterFigure3d"
+                                                class="character-3d-frame character-3d-frame--compact"
+                                                :style="getChild3dBackgroundStyle(child)"
+                                            >
                                                 <Character3D
                                                     :gender="child.gender"
                                                     :age="child.age"
@@ -1155,6 +1159,23 @@ export default {
             };
         },
 
+        getChild3dBackgroundStyle(child) {
+            const childKey = String(child?.childCharacterId || child?.id || child?.name || 'child');
+            let hash = 0;
+            for (let index = 0; index < childKey.length; index += 1) {
+                hash = ((hash << 5) - hash + childKey.charCodeAt(index)) | 0;
+            }
+
+            const backgroundNumber = (hash >>> 0) % 5 + 1;
+            return {
+                backgroundColor: '#dff1ee',
+                backgroundImage: `url(/images/falukant/backgrounds/family-child-${backgroundNumber}.png)`,
+                backgroundPosition: 'center',
+                backgroundRepeat: 'no-repeat',
+                backgroundSize: 'cover',
+            };
+        },
+
         formatCost(value) {
             return new Intl.NumberFormat(navigator.language, { minimumFractionDigits: 2, maximumFractionDigits: 2 }).format(value);
         },
@@ -1870,6 +1891,7 @@ export default {
     border-radius: var(--radius-lg);
     background-color: var(--color-surface-accent);
     flex-shrink: 0;
+    overflow: hidden;
 }
 
 .character-3d-frame--spouse {