fix: file picker in app not working with mrpack

apps/app-frontend/src/providers/setup/file-picker.ts

@@ -1,6 +1,17 @@
 import { provideFilePicker } from '@modrinth/ui'
 import { convertFileSrc } from '@tauri-apps/api/core'
 import { open } from '@tauri-apps/plugin-dialog'
+import { readFile } from '@tauri-apps/plugin-fs'
+
+function getFileName(path: string, fallback: string) {
+	return path.split(/[\\/]/).pop() || fallback
+}
+
+async function createFileFromPath(path: string, fallbackName: string, type?: string) {
+	const bytes = await readFile(path)
+	const name = getFileName(path, fallbackName)
+	return new File([bytes], name, type ? { type } : undefined)
+}
 
 export function setupFilePickerProvider() {
 	provideFilePicker({
@@ -12,8 +23,7 @@ export function setupFilePickerProvider() {
 			if (!result) return null
 			const path = result.path ?? result
 			if (!path) return null
-			const name = path.split(/[\\/]/).pop() || 'icon'
-			const file = new File([], name)
+			const file = await createFileFromPath(path, 'icon')
 			return { file, path, previewUrl: convertFileSrc(path) }
 		},
 		async pickModpackFile() {
@@ -24,8 +34,11 @@ export function setupFilePickerProvider() {
 			if (!result) return null
 			const path = result.path ?? result
 			if (!path) return null
-			const name = path.split(/[\\/]/).pop() || 'modpack.mrpack'
-			const file = new File([], name)
+			const file = await createFileFromPath(
+				path,
+				'modpack.mrpack',
+				'application/x-modrinth-modpack+zip',
+			)
 			return { file, path, previewUrl: '' }
 		},
 	})