feat: layout url import

feat: backup import (except chords)
feat: legacy layout import
feat: separate layout, chord & setting backup downloads

src/routes/+layout.ts

@@ -1,2 +1,14 @@
+import type {LayoutLoad} from "./$types"
+import {browser} from "$app/environment"
+import {charaFileFromUriComponent} from "$lib/share/share-url"
+
 export const prerender = true
 export const trailingSlash = "always"
+
+export const load = (async ({url, data, fetch}) => {
+  const importFile = new URLSearchParams(url.search).get("import")
+  return {
+    ...data,
+    importFile: browser && importFile ? await charaFileFromUriComponent(importFile, fetch) : undefined,
+  }
+}) satisfies LayoutLoad