COMP-1146 Fix error messages

[munishchouhan]

Summary

Improves error handling by introducing a sanitized ErrorResponse model that prevents exposure of internal implementation details in API error responses.

Changes

• New ErrorResponse class: Standardized error response model with timestamp, status, error type, message, request ID, and path
• Enhanced ErrorController: Added specific error handlers for common exceptions (JSON parsing, validation, conversion errors) with sanitized user-friendly messages and
  request ID tracking for debugging
• Comprehensive test coverage: Added ErrorHandlingTest to verify error sanitization and proper HTTP status codes

Benefits

• Prevents leakage of sensitive internal implementation details in error responses
• Provides consistent error response format across all endpoints
• Includes request IDs for easier debugging while keeping responses user-friendly
• Improves security posture by sanitizing error messages