refactor(services): rename EbookScanner to MediaScanner

- Rename EbookScanner struct to MediaScanner
- Rename EbookMetadata struct to MediaMetadata
- Rename NewEbookScanner to NewMediaScanner
- Rename processEbookFile to processMediaFile
- Rename updateEbook to updateMediaItem
- Rename getEbookByFilePath to getMediaItemByFilePath
- Remove unused isEbookFile method
- Update all method receivers
- Update variable names (ebookFiles -> mediaFiles, existingEbook -> existingItem)
- Update print statements to use 'media' terminology
- Update worker.go to use NewMediaScanner
- File renamed: ebook_scanner.go -> media_scanner.go

internal/services/worker.go

@@ -170,7 +170,7 @@ func (w *Worker) processScanJob(job *Job) (interface{}, error) {
 		return nil, fmt.Errorf("database queries required")
 	}
 
-	scanner := NewEbookScanner(db)
+	scanner := NewMediaScanner(db)
 
 	if err := scanner.SetFolders(folders); err != nil {
 		return nil, err