feat(svelte): add SvelteFlowProvider and useSvelteFlow hook

packages/svelte/src/lib/hooks/useSvelteFlow.ts

@@ -0,0 +1,19 @@
+import type { ZoomInOut } from '@reactflow/system';
+
+import { useStore } from '$lib/store';
+import type { FitViewOptions } from '$lib/types';
+
+export function useSvelteFlow(): {
+  zoomIn: ZoomInOut;
+  zoomOut: ZoomInOut;
+  fitView: (options?: FitViewOptions) => void;
+} {
+  // how to get the new context here? fit view doesn't work, because the store is not updated (uses old nodes store)
+  const { zoomIn, zoomOut, fitView } = useStore();
+
+  return {
+    zoomIn,
+    zoomOut,
+    fitView
+  };
+}