refactor(mcp): improve UI consistency and i18n

- Add MCP-specific green button style (buttonStyles.mcp)
- Unify MCP panel and form buttons with emerald theme
- Adjust MCP entry button width to match AppSwitcher (px-3)
- Reduce JSON editor height from h-64 to h-48
- Update translations: "Add/Edit Server" → "Add/Edit MCP"
- Change form label to "MCP Title (Unique)" for clarity
- Move config wizard button to right side of JSON label
- Fix McpListItem enabled state check (explicit true check)

src/lib/styles.ts

@@ -16,6 +16,10 @@ export const buttonStyles = {
   danger:
     "px-4 py-2 bg-red-500 text-white rounded-lg hover:bg-red-600 dark:bg-red-600 dark:hover:bg-red-700 transition-colors text-sm font-medium",
 
+  // MCP 专属按钮：绿底白字
+  mcp:
+    "px-4 py-2 bg-emerald-500 text-white rounded-lg hover:bg-emerald-600 dark:bg-emerald-600 dark:hover:bg-emerald-700 transition-colors text-sm font-medium",
+
   // 幽灵按钮：无背景，仅悬浮反馈
   ghost:
     "px-4 py-2 text-gray-500 hover:text-gray-900 hover:bg-gray-100 dark:text-gray-400 dark:hover:text-gray-100 dark:hover:bg-gray-800 rounded-lg transition-colors text-sm font-medium",