Enhancement: Improve metadata lookup error handling and logging

[mapitman]

Enhance null safety and error handling in metadata lookups:

Location: src/RipSharp/MetadataService.cs

Suggestions:

• Create explicit result types (MetadataResult with status)
• Log why lookups fail rather than silent catches
• Consider retry logic for transient failures
• Better distinction between not-found vs error cases

Priority: Low - Works well currently but could be more explicit and robust