- Add CreateProcessingIssue with upsert for recording/renewing issues
- Add ListProcessingIssuesByLibrary with severity ordering and media item details
- Add GetProcessingIssueStats for error/warning/info counts
- Add ResolveProcessingIssue for marking issues as resolved
- Add DeleteProcessingIssue for removing resolved issues
- Add GetLibraryWithType for fetching library with type info for validation