refactor: enhance onboarding experience

- Replaced the completion step component with a more streamlined onboarding page that includes action cards for managing teams, adding sources, and starting chats.
- Updated the search space form to make the description field optional and improved validation messages.
- Adjusted the onboarding logic to support auto-configuration of LLM roles and improved loading states.
- Removed unused imports and components to clean up the codebase.

surfsense_web/components/onboard/index.ts

@@ -0,0 +1,8 @@
+export { OnboardActionCard } from "./onboard-action-card";
+export { OnboardAdvancedSettings } from "./onboard-advanced-settings";
+export { OnboardHeader } from "./onboard-header";
+export { OnboardLLMSetup } from "./onboard-llm-setup";
+export { OnboardLoading } from "./onboard-loading";
+export { OnboardStats } from "./onboard-stats";
+export { SetupLLMStep } from "./setup-llm-step";
+export { SetupPromptStep } from "./setup-prompt-step";