🔑 refactor: MCP Settings Rendering Logic for OAuth Servers (#8718)

* feat: add OAuth servers to conditional rendering logic for MCPPanel in SideNav

* feat: add startup flag check to conditional rendering logic

* fix: correct improper handling of failure state in reinitialize endpoint

* fix: change MCP config components to better handle servers without customUserVars

- removes the subtle reinitialize button from config components of servers without customUserVars or OAuth
- adds a placeholder message for components where servers have no customUserVars configured

* style: swap CustomUserVarsSection and ServerInitializationSection positions

* style: fix coloring for light mode and align more with existing design patterns

* chore: remove extraneous comments

* chore: reorder imports and `isEnabled` from api package

---------

Co-authored-by: Danny Avila <danny@librechat.ai>

client/src/locales/en/translation.json

@@ -506,6 +506,7 @@
   "com_sidepanel_hide_panel": "Hide Panel",
   "com_sidepanel_manage_files": "Manage Files",
   "com_sidepanel_mcp_no_servers_with_vars": "No MCP servers with configurable variables.",
+  "com_sidepanel_mcp_no_custom_vars": "No custom user variables set for {{0}}",
   "com_sidepanel_mcp_variables_for": "MCP Variables for {{0}}",
   "com_sidepanel_parameters": "Parameters",
   "com_sources_image_alt": "Search result image",
@@ -851,7 +852,6 @@
   "com_ui_mcp_authenticated_success": "MCP server '{{0}}' authenticated successfully",
   "com_ui_mcp_dialog_desc": "Please enter the necessary information below.",
   "com_ui_mcp_enter_var": "Enter value for {{0}}",
-  "com_ui_mcp_init_cancelled": "MCP server '{{0}}' initialization was cancelled due to simultaneous request",
   "com_ui_mcp_init_failed": "Failed to initialize MCP server",
   "com_ui_mcp_initialize": "Initialize",
   "com_ui_mcp_initialized_success": "MCP server '{{0}}' initialized successfully",