✨ feat: Configurable MCP Dropdown Placeholder (#7988)

* new env  variable for mcp label

* 🔄 refactor: Update MCPSelect placeholderText to draw from interface section of librechat.yaml rather than .env

* 🧹 chore: extract mcpServers schema for better maintainability

* 🔄 refactor: Update MCPSelect and useMCPSelect to utilize TPlugin type for better type consistency

* 🔄 refactor: Pass placeholder from startupConfig to MCPSubMenu for improved localization

* 🔄 refactor: Integrate startupConfig into BadgeRowContext and related components for enhanced configuration management

---------

Co-authored-by: mwbrandao <mariana.brandao@nos.pt>
Co-authored-by: Danny Avila <danny@librechat.ai>

client/src/components/Chat/Input/ToolsDropdown.tsx

@@ -18,8 +18,15 @@ const ToolsDropdown = ({ disabled }: ToolsDropdownProps) => {
   const localize = useLocalize();
   const isDisabled = disabled ?? false;
   const [isPopoverActive, setIsPopoverActive] = useState(false);
-  const { webSearch, codeInterpreter, fileSearch, mcpSelect, searchApiKeyForm, codeApiKeyForm } =
-    useBadgeRowContext();
+  const {
+    webSearch,
+    mcpSelect,
+    fileSearch,
+    startupConfig,
+    codeApiKeyForm,
+    codeInterpreter,
+    searchApiKeyForm,
+  } = useBadgeRowContext();
   const { setIsDialogOpen: setIsCodeDialogOpen, menuTriggerRef: codeMenuTriggerRef } =
     codeApiKeyForm;
   const { setIsDialogOpen: setIsSearchDialogOpen, menuTriggerRef: searchMenuTriggerRef } =
@@ -89,6 +96,8 @@ const ToolsDropdown = ({ disabled }: ToolsDropdownProps) => {
     [mcpSelect],
   );
 
+  const mcpPlaceholder = startupConfig?.interface?.mcpServers?.placeholder;
+
   const dropdownItems = useMemo(() => {
     const items: MenuItemProps[] = [
       {
@@ -246,8 +255,9 @@ const ToolsDropdown = ({ disabled }: ToolsDropdownProps) => {
           <MCPSubMenu
             {...props}
             mcpValues={mcpValues}
-            mcpServerNames={mcpServerNames}
             isMCPPinned={isMCPPinned}
+            placeholder={mcpPlaceholder}
+            mcpServerNames={mcpServerNames}
             setIsMCPPinned={setIsMCPPinned}
             handleMCPToggle={handleMCPToggle}
           />
@@ -262,6 +272,7 @@ const ToolsDropdown = ({ disabled }: ToolsDropdownProps) => {
     canRunCode,
     isMCPPinned,
     isCodePinned,
+    mcpPlaceholder,
     mcpServerNames,
     isSearchPinned,
     setIsMCPPinned,