add-error-handling

Implement comprehensive error handling for current code to make it robust and resilient while maintaining good UX.

1. Error Detection: Identify potential failure points, edge cases, unhandled exceptions, missing validation, async/network call issues
2. Error Handling Strategy: Implement try-catch blocks, add input validation/sanitization, create meaningful error messages/logging, design graceful degradation
3. Recovery Mechanisms: Implement retry logic for transient failures, add fallback options, create circuit breakers, design proper error propagation
4. User Experience: Provide clear error messages, implement proper error status codes for APIs, add loading states/error boundaries for UI, include helpful suggestions

Follow apps/docu/content/docs/architecture/error-handling.mdx.