feat(mcp): add streamable HTTP and stdio (#1911)

* feat(mcp): add streamable HTTP

alongside with frontend UI change, w/ support for stdio

* fix(mcp): address copilot reviews

* Update src/langbot/pkg/provider/tools/loaders/mcp.py

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* fix: resolve copilot reviews

* fix: Message -> MessageChunk

* feat: upgrade mcp module

* feat: add i18n

* feat(mcp): enhance MCPCardComponent with mode badge and reorder select items in MCPFormDialog

---------

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
Co-authored-by: WangCham <651122857@qq.com>
Co-authored-by: Junyan Qin (Chin) <rockchinq@gmail.com>

web/src/i18n/locales/zh-Hans.ts

@@ -446,8 +446,10 @@ const zhHans = {
     getServerListError: '获取 MCP 服务器列表失败：',
     serverName: '服务器名称',
     serverMode: '连接模式',
+    selectMode: '选择模式',
     stdio: 'Stdio模式',
     sse: 'SSE模式',
+    http: 'HTTP模式',
     noServerInstalled: '暂未配置任何 MCP 服务器',
     serverNameRequired: '服务器名称不能为空',
     commandRequired: '命令不能为空',