Feat: spell check toggle for desktop (#626)

* feat: (desktop) add spellcheck toggle for text inputs

* fix: show spellcheck toggle only on desktop

* fix: apply the preference consistently to chat and commit inputs

packages/ui/src/lib/api/types.ts

@@ -525,6 +525,7 @@ export interface SettingsPayload {
   queueModeEnabled?: boolean;
   gitmojiEnabled?: boolean;
   toolCallExpansion?: 'collapsed' | 'activity' | 'detailed' | 'changes';
+  inputSpellcheckEnabled?: boolean;
   fontSize?: number;
   terminalFontSize?: number;
   padding?: number;