style: remove hyphens from compound adjectives in comments and messages

Remove hyphens from compound adjectives such as "logged-in", "one-time", "password-protected", "full-height", "multi-file", and "S3-compatible" in comments, test error messages, and UI labels to improve readability and consistency.

backend/libs/services/upload.go

@@ -306,7 +306,7 @@ func (s *UploadService) CreateBoxFromIncomingContext(ctx context.Context, files
 	var expiresAt time.Time
 	switch {
 	case opts.ExpiresInMinutes < 0 || opts.MaxDays < 0:
-		// "Forever" — a date far enough out that the box effectively never
+		// "Forever". a date far enough out that the box effectively never
 		// expires. No schema change; CanDownload/cleanup keep working as-is.
 		expiresAt = now.AddDate(100, 0, 0)
 	case opts.ExpiresInMinutes > 0:
@@ -361,7 +361,7 @@ func (s *UploadService) CreateBoxFromIncomingContext(ctx context.Context, files
 	return s.resultForBox(box, deleteToken), nil
 }
 
-// AppendFiles adds files to an existing box (used to group a ShareX multi-file
+// AppendFiles adds files to an existing box (used to group a ShareX multiple file
 // selection into a single box). The box keeps its original expiry, password and
 // other settings; only the new files are written.
 func (s *UploadService) AppendFiles(boxID string, files []*multipart.FileHeader, opts UploadOptions) (UploadResult, error) {
@@ -1099,7 +1099,7 @@ func (s *UploadService) resultForBox(box Box, deleteToken string) UploadResult {
 	}
 
 	// The box-level thumbnail points at the most recently added file, so a
-	// per-file ShareX upload previews the file it just sent.
+	// per file ShareX upload previews the file it just sent.
 	thumbnailURL := fmt.Sprintf("%s/d/%s/og-image.jpg", s.baseURL, box.ID)
 	if len(files) > 0 {
 		thumbnailURL = files[len(files)-1].ThumbnailURL