auto-claude: subtask-1-1 - Add onboardingCompleted to AppSettings type interface

Add optional onboardingCompleted boolean field to AppSettings interface
to track whether the user has completed the onboarding wizard.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

auto-claude-ui/src/shared/types/settings.ts

@@ -16,6 +16,8 @@ export interface AppSettings {
   // Global API keys (used as defaults for all projects)
   globalClaudeOAuthToken?: string;
   globalOpenAIApiKey?: string;
+  // Onboarding wizard completion state
+  onboardingCompleted?: boolean;
 }
 
 // Auto-Claude Source Environment Configuration (for auto-claude repo .env)