Improve error messages across handlers

Description

Many handlers currently return generic error messages like 'Failed to create customer' without providing specific details about what went wrong. This makes debugging difficult for users.

Current Problem

Example from handlers: \\ ypescript error: response.error || 'Failed to create customer' \`n

Proposed Solution

Enhance error messages to include:

• Specific error details from QuickBooks API
• Field-level validation errors
• HTTP status codes
• Suggested actions for common errors

Requirements

• Review error handling in at least 3 handler files
• Extract detailed error information from API responses
• Create helper function for consistent error formatting
• Add specific error messages for common scenarios
• Document error response format

Example Implementation

\\ ypescript function formatDetailedError(error: any, operation: string): string { const baseMessage = \Failed to \; if (error.response?.data) { const qbError = error.response.data.Fault?.Error?.[0]; if (qbError) { return \: \ (Code: ); } } return baseMessage; } \`n

Benefits

• Better developer experience
• Easier debugging
• Clearer API documentation
• Reduced support requests