Improve error handling throughout codebase #5
Description
Description
Add comprehensive error handling with helpful error messages throughout the codebase.
Critical Areas
- XML parsing errors (catch ElementTree exceptions)
- Encoding errors (UnicodeDecodeError)
- CSV parsing errors (malformed CSV)
- JSON parsing errors (already handled, improve messages)
- File not found errors (improve messages)
- Permission errors
- Disk space errors
Error Message Improvements
- Add suggestions for common errors
- Show context (line numbers for JSON/XML errors)
- Suggest correct flags/formats
- Add --debug flag for full tracebacks
Success Criteria
- All exception types caught appropriately
- Error messages are helpful and actionable
- No silent failures
- Tests for error conditions