chore(zIndexMode): use basic as default

packages/svelte/src/lib/container/SvelteFlow/types.ts

@@ -505,7 +505,7 @@ export type SvelteFlowProps<
      * Used to define how z-indexing is calculated for nodes and edges.
      * 'auto' is for selections and sub flows, 'basic' for selections only, and 'manual' for no auto z-indexing.
      *
-     * @default 'auto'
+     * @default 'basic'
      */
     zIndexMode?: ZIndexMode;
   };

packages/svelte/src/lib/store/initial-store.svelte.ts

@@ -117,7 +117,7 @@ export function getInitialStore<NodeType extends Node = Node, EdgeType extends E
     panZoom: PanZoomInstance | null = $state.raw(null);
     width = $state.raw<number>(signals.width ?? 0);
     height = $state.raw<number>(signals.height ?? 0);
-    zIndexMode = $state.raw<ZIndexMode>(signals.props.zIndexMode ?? 'auto');
+    zIndexMode = $state.raw<ZIndexMode>(signals.props.zIndexMode ?? 'basic');
 
     nodesInitialized: boolean = $derived.by(() => {
       const nodesInitialized = adoptUserNodes(signals.nodes, this.nodeLookup, this.parentLookup, {