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-Hant.ts

@@ -445,6 +445,8 @@ const zhHant = {
     serverMode: '連接模式',
     stdio: 'Stdio模式',
     sse: 'SSE模式',
+    selectMode: '選擇連接模式',
+    http: 'HTTP模式',
     noServerInstalled: '暫未設定任何MCP伺服器',
     serverNameRequired: '伺服器名稱不能為空',
     commandRequired: '命令不能為空',