feat(svelte): add SvelteFlowProvider and useSvelteFlow hook

packages/svelte/src/lib/components/SvelteFlowProvider/SvelteFlowProvider.svelte

@@ -0,0 +1,13 @@
+<script lang="ts">
+  import { setContext } from 'svelte';
+  
+  import { createStore, key } from '$lib/store';
+
+  const store = createStore();
+
+  setContext(key, {
+    getStore: () => store
+  });
+</script>
+
+<slot />

packages/svelte/src/lib/components/SvelteFlowProvider/index.ts

@@ -0,0 +1,2 @@
+export { default as SvelteFlowProvider } from './SvelteFlowProvider.svelte';
+export type { SvelteFlowProviderProps } from './types';

packages/svelte/src/lib/components/SvelteFlowProvider/types.ts

@@ -0,0 +1,6 @@
+import type { SvelteFlowProps } from '$lib/container/SvelteFlow/types';
+
+export type SvelteFlowProviderProps = Pick<
+  SvelteFlowProps,
+  'nodes' | 'edges' | 'fitView' | 'nodeTypes'
+>;