feat: implement project launch script run.sh and update README

backend/src/plugins/backup.py

@@ -58,7 +58,7 @@ class BackupPlugin(PluginBase):
                     "type": "string",
                     "title": "Environment",
                     "description": "The Superset environment to back up.",
-                    "enum": envs if envs else ["dev", "prod"],
+                    "enum": envs if envs else [],
                 },
                 "backup_path": {
                     "type": "string",
@@ -79,6 +79,9 @@ class BackupPlugin(PluginBase):
 
         try:
             config_manager = get_config_manager()
+            if not config_manager.has_environments():
+                raise ValueError("No Superset environments configured. Please add an environment in Settings.")
+                
             clients = setup_clients(logger, custom_envs=config_manager.get_environments())
             client = clients.get(env)