feat: Implement extension and bot limitations across services and UI (#1991)

- Added checks for maximum allowed extensions, bots, and pipelines in the backend services (PluginsRouterGroup, BotService, MCPService, PipelineService).
- Updated system configuration to include limitation settings for max_bots, max_pipelines, and max_extensions.
- Enhanced frontend components to handle limitations, providing user feedback when limits are reached.
- Added internationalization support for limitation messages in English, Japanese, Simplified Chinese, and Traditional Chinese.

src/langbot/templates/config.yaml

@@ -15,8 +15,13 @@ proxy:
     http: ''
     https: ''
 system:
+    edition: community
     recovery_key: ''
     allow_modify_login_info: true
+    limitation:
+        max_bots: -1
+        max_pipelines: -1
+        max_extensions: -1
     jwt:
         expire: 604800
         secret: ''