feat: disable letter cache (#446)

Fixes #445

lib/view/page/setting/entry.dart

@@ -156,6 +156,7 @@ class _SettingPageState extends State<SettingPage> {
   Widget _buildSSH() {
     return Column(
       children: [
+        _buildLetterCache(),
         _buildSSHWakeLock(),
         _buildTermTheme(),
         _buildFont(),
@@ -1178,4 +1179,16 @@ class _SettingPageState extends State<SettingPage> {
       trailing: StoreSwitch(prop: _setting.betaTest),
     );
   }
+
+  Widget _buildLetterCache() {
+    return ListTile(
+      leading: const Icon(Bootstrap.input_cursor),
+      title: Text(l10n.letterCache),
+      subtitle: Text(
+        '${l10n.letterCacheTip}\n${l10n.needRestart}',
+        style: UIs.textGrey,
+      ),
+      trailing: StoreSwitch(prop: _setting.letterCache),
+    );
+  }
 }

lib/view/page/ssh/page.dart

@@ -129,6 +129,7 @@ class SSHPageState extends State<SSHPage>
   }
 
   Widget _buildBody() {
+    final letterCache = Stores.setting.letterCache.fetch();
     return SizedBox(
       height: _media.size.height -
           _virtKeysHeight -
@@ -144,8 +145,10 @@ class SSHPageState extends State<SSHPage>
           _terminal,
           key: _termKey,
           controller: _terminalController,
-          keyboardType: TextInputType.text,
-          enableSuggestions: true,
+          keyboardType: letterCache
+              ? TextInputType.text
+              : TextInputType.visiblePassword,
+          enableSuggestions: !letterCache,
           textStyle: _terminalStyle,
           theme: _terminalTheme,
           deleteDetection: isMobile,