Move overlapping childless spouses to nearest row edge

After Y-snapping, spouses without shared children can land on top of
each other. Detect these overlaps and move the spouse to the nearest
edge of the generation row without affecting other cards.

resources/js/modules/lib/layout/elk-layout.js

@@ -317,6 +317,47 @@ function extractPositions(elkResult, builder, config) {
         }
     }
 
+    // ── Step 2b: Fix overlapping spouses (childless couples) ──
+    // After Y-snapping, spouses without shared children may land on top of
+    // each other. Move the overlapping spouse to the nearest row edge.
+    const minGap = config.cardWidth + config.horizontalSpacing;
+
+    for (const [id, person] of builder.personById) {
+        const spouseIds = (person.rels.spouses || []).filter((sid) =>
+            builder.personById.has(sid)
+        );
+        if (spouseIds.length === 0) continue;
+
+        const pos = posMap.get(id);
+        if (!pos) continue;
+
+        for (const sid of spouseIds) {
+            const spos = posMap.get(sid);
+            if (!spos) continue;
+
+            // Check if they overlap (same row after Y-snap, too close on X)
+            if (Math.abs(pos.y - spos.y) > 1) continue;
+            if (Math.abs(pos.x - spos.x) >= minGap) continue;
+
+            // Find the row extents (min/max X of all persons in this gen)
+            const gen = builder.generations.get(sid) ?? 0;
+            const rowIds = genGroups.get(gen) || [];
+            const rowXs = rowIds
+                .map((rid) => posMap.get(rid)?.x)
+                .filter((x) => x !== undefined);
+            const rowMin = Math.min(...rowXs);
+            const rowMax = Math.max(...rowXs);
+
+            // Place at left or right edge, whichever is closer to current pos
+            const leftTarget = rowMin - minGap;
+            const rightTarget = rowMax + minGap;
+            const distLeft = Math.abs(spos.x - leftTarget);
+            const distRight = Math.abs(spos.x - rightTarget);
+
+            spos.x = distLeft <= distRight ? leftTarget : rightTarget;
+        }
+    }
+
     // ── Step 3: Build edge maps ──
     const incomingToUnion = new Map();
     const outgoingFromUnion = new Map();