new: use generated ids for servers (#765)

* new: use generated ids for servers
Fixes #743

* fix: deps.

* fix: migrate related settings

* fix: restore servers from json

lib/view/page/backup.dart

@@ -251,7 +251,7 @@ final class _BackupPageState extends State<BackupPage>
       onTap: () async {
         final data = await context.showImportDialog(
           title: l10n.snippet,
-          modelDef: SnippetX.example.toJson(),
+          modelDef: Snippet.example.toJson(),
         );
         if (data == null) return;
         final str = String.fromCharCodes(data);

lib/view/page/server/edit.dart

@@ -672,6 +672,7 @@ extension on _ServerEditPageState {
       custom: custom,
       wolCfg: wol,
       envs: _env.value.isEmpty ? null : _env.value,
+      id: widget.args?.spi.id ?? ShortId.generate(),
     );
 
     if (this.spi == null) {

lib/view/page/setting/entry.dart

@@ -118,7 +118,6 @@ final class _AppSettingsPageState extends State<AppSettingsPage> {
   @override
   Widget build(BuildContext context) {
     return MultiList(
-      thumbVisibility: true,
       children: [
         [const CenterGreyTitle('App'), _buildApp()],
         [CenterGreyTitle(l10n.server), _buildServer()],