Feat/pipeline enable all extensions (#1807)

* feat: 添加流水线扩展集成"启用所有"选项

为流水线的扩展集成配置添加独立的"启用所有插件"和"启用所有MCP服务器"选项。

主要变更：
- 数据模型：在 extensions_preferences 中添加 enable_all_plugins 和 enable_all_mcp_servers 字段
- 后端逻辑：修改 RuntimePipeline 以支持独立的启用所有选项，当启用时设置为 None 表示使用所有可用资源
- API 接口：更新 GET/PUT /api/v1/pipelines/{uuid}/extensions 以支持新字段
- 前端 UI：为插件和 MCP 服务器分别添加独立的开关控件
- 国际化：添加对应的中文翻译文本
- 默认行为：新创建的流水线默认启用所有插件和 MCP 服务器

🤖 Generated with [Claude Code](https://claude.com/claude-code)
via [Happy](https://happy.engineering)

Co-Authored-By: Claude <noreply@anthropic.com>
Co-Authored-By: Happy <yesreply@happy.engineering>

* fix(i18n): add missing translations for pipeline extensions

Added translations for enable all plugins/MCP servers feature:
- en-US: English translations
- ja-JP: Japanese translations
- zh-Hant: Traditional Chinese translations

Generated with [Claude Code](https://claude.ai/code)
via [Happy](https://happy.engineering)

Co-Authored-By: Claude <noreply@anthropic.com>
Co-Authored-By: Happy <yesreply@happy.engineering>

* chore: add migration for enable all extensions config

* fix: bad renaming

---------

Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: Happy <yesreply@happy.engineering>

src/langbot/pkg/entity/persistence/pipeline.py

@@ -22,7 +22,11 @@ class LegacyPipeline(Base):
     is_default = sqlalchemy.Column(sqlalchemy.Boolean, nullable=False, default=False)
     stages = sqlalchemy.Column(sqlalchemy.JSON, nullable=False)
     config = sqlalchemy.Column(sqlalchemy.JSON, nullable=False)
-    extensions_preferences = sqlalchemy.Column(sqlalchemy.JSON, nullable=False, default={})
+    extensions_preferences = sqlalchemy.Column(
+        sqlalchemy.JSON,
+        nullable=False,
+        default={'enable_all_plugins': True, 'enable_all_mcp_servers': True, 'plugins': [], 'mcp_servers': []},
+    )
 
 
 class PipelineRunRecord(Base):