change file permissions to /uploads

backend/handlers/handle_message_upload.go

@@ -48,6 +48,11 @@ func (store *Store) UploadMessageFile(ctx *gin.Context) {
 		ctx.JSON(http.StatusInternalServerError, gin.H{"error": "failed to create upload directory"})
 		return
 	}
+	// Ensure directory is world-readable so nginx can serve files
+	if err := os.Chmod(uploadDir, 0755); err != nil {
+		ctx.JSON(http.StatusInternalServerError, gin.H{"error": "failed to create upload directory"})
+		return
+	}
 
 	dest := filepath.Join(uploadDir, filename)
 	if err := ctx.SaveUploadedFile(file, dest); err != nil {