Implement standardized error handling with FumeError type

[benny779]

• Add FumeError type extending JsonataError with standardized fields
• Create createFumeError factory function for consistent error formatting
• Export FumeError types and factory from types module
• Update root controller to use createFumeError instead of inline error object
• Update mapping controller to use createFumeError and proper error typing
• Standardize error responses with 422 status code for processing errors