fix: keep isDragging true until lanes state is updated

The $effect that syncs laneData from orderedLanes was firing when
isDragging was set to false, overwriting the optimistic sort order
with stale data. Now isDragging stays true until after lanes state
is updated with the new sort order, so the $effect sees correct data.

web/src/routes/[workspace]/roles/+page.svelte

@@ -99,19 +99,20 @@
 	async function handleDndFinalize(key: string, e: CustomEvent<DndEvent<Item>>) {
 		const finalItems = e.detail.items.filter((i: any) => !i[SHADOW_ITEM_MARKER_PROPERTY_NAME]);
 		laneData[key] = finalItems;
-		isDragging = false;
+
+		// Keep isDragging true until lanes state is updated,
+		// so the $effect doesn't overwrite laneData from stale orderedLanes.
 
 		const { id: itemId, trigger } = e.detail.info;
 
 		if (trigger === TRIGGERS.DROPPED_INTO_ZONE) {
 			// Cross-lane move — update the item's role
 			const originalItem = orderedLanes.flatMap((l) => l.items).find((i) => i.id === itemId);
-			if (!originalItem) return;
+			if (!originalItem) { isDragging = false; return; }
 
 			const oldKey = originalItem.agent_role_id ?? '__unassigned';
-			if (oldKey === key) return;
+			if (oldKey === key) { isDragging = false; return; }
 
-			// Optimistic update: move item in `lanes`
 			const newRoleId = key === '__unassigned' ? null : key;
 			const targetRole = orderedLanes.find((l) => laneKey(l) === key)?.role ?? null;
 
@@ -151,6 +152,7 @@
 			} catch (err) {
 				console.error('Failed to update role:', err);
 				await loadData();
+				isDragging = false;
 				return;
 			}
 		}
@@ -161,12 +163,15 @@
 			role_sort_order: index
 		}));
 
-		// Optimistic: update lanes state with new sort orders
+		// Optimistic: update lanes state with new sort orders BEFORE releasing isDragging
 		lanes = lanes.map((lane) => {
 			if (laneKey(lane) !== key) return lane;
 			return { ...lane, items: finalItems.map((item, index) => ({ ...item, role_sort_order: index })) };
 		});
 
+		// Now safe to release — lanes has the correct data for the $effect to sync from
+		isDragging = false;
+
 		try {
 			await api.agentRoles.reorder(wsSlug, reorderUpdates);
 		} catch (err) {