refactor(services): remove debug logging and fix directory scanning

- Remove debug printf statements from media scanner and worker
- Remove unused debug tracking variables (filesSeen, filesProcessed)
- Fix directory walk logic to properly scan the root directory itself
  (previous implementation would skip the root path entirely)

Clean up production code by removing debug artifacts and improving
the directory scanning logic to handle root-level directories correctly.

internal/services/worker.go

@@ -910,9 +910,6 @@ func (w *Worker) processDirectoryScanJob(job *Job) (interface{}, error) {
 	}
 	// Now scan the directory
 	scanner.scanDirectory(ctx, directory)
-	// Debug logging
-	fmt.Printf("DEBUG: scanDirectory completed - totalFiles: %d, newItems: %d, errors: %d\n",
-		scanner.totalFiles, scanner.newItems, scanner.errors)
 
 	// Return scan results
 	return &DirectoryScanJobResult{