🔌 refactor: MCP UI with Improved Accessibility and Reusable Components (#11118)

* feat: enhance MCP server selection UI with new components and improved accessibility

* fix(i18n): add missing com_ui_mcp_servers translation key

The MCP server menu aria-label was referencing a non-existent translation
key. Added the missing key for accessibility.

* feat(MCP): enhance MCP components with improved accessibility and focus management

* fix(i18n): remove outdated MCP server translation keys

* fix(MCPServerList): improve color contrast by updating text color for no MCP servers message

* refactor(MCP): Server status components and improve user action handling
Updated MCPServerStatusIcon to use a unified icon system for better clarity
Introduced new MCPCardActions component for standardized action buttons on server cards
Created MCPServerCard component to encapsulate server display logic and actions
Enhanced MCPServerList to render MCPServerCard components, improving code organization
Added MCPStatusBadge for consistent status representation in dialogs
Updated utility functions for status color and text retrieval to align with new design
Improved localization keys for better clarity and consistency in user messages

* style(MCP): update button and card background styles for improved UI consistency

* feat(MCP): implement global server initialization state management using Jotai

* refactor(MCP): modularize MCPServerDialog into structured component architecture

- Split monolithic dialog into dedicated section components (Auth, BasicInfo, Connection, Transport, Trust)
- Extract form logic into useMCPServerForm custom hook
- Add utility modules for JSON import and URL handling
- Introduce reusable SecretInput component in @librechat/client
- Remove deprecated MCPAuth component

* style(MCP): update button styles for improved layout and adjust empty state background color

* refactor(Radio): enhance component mounting logic and background style updates

* refactor(translation): remove unused keys and streamline localization strings

client/src/locales/en/translation.json

@@ -535,8 +535,16 @@
   "com_nav_long_audio_warning": "Longer texts will take longer to process.",
   "com_nav_maximize_chat_space": "Maximize chat space",
   "com_nav_mcp_configure_server": "Configure {{0}}",
+  "com_nav_mcp_connect": "Connect",
+  "com_nav_mcp_connect_server": "Connect {{0}}",
+  "com_nav_mcp_reconnect": "Reconnect",
   "com_nav_mcp_status_connected": "Connected",
-  "com_nav_mcp_status_connecting": "{{0}} - Connecting",
+  "com_nav_mcp_status_connecting": "Connecting",
+  "com_nav_mcp_status_disconnected": "Disconnected",
+  "com_nav_mcp_status_error": "Error",
+  "com_nav_mcp_status_initializing": "Initializing",
+  "com_nav_mcp_status_needs_auth": "Needs Auth",
+  "com_nav_mcp_status_unknown": "Unknown",
   "com_nav_mcp_vars_update_error": "Error updating MCP custom user variables",
   "com_nav_mcp_vars_updated": "MCP custom user variables updated successfully.",
   "com_nav_modular_chat": "Enable switching Endpoints mid-conversation",
@@ -639,7 +647,6 @@
   "com_ui_additional_details": "Additional Details",
   "com_ui_admin": "Admin",
   "com_ui_admin_access_warning": "Disabling Admin access to this feature may cause unexpected UI issues requiring refresh. If saved, the only way to revert is via the interface setting in librechat.yaml config which affects all roles.",
-  "com_ui_admin_provides_key": "Provide a key for all users",
   "com_ui_admin_settings": "Admin Settings",
   "com_ui_admin_settings_section": "Admin Settings - {{section}}",
   "com_ui_advanced": "Advanced",
@@ -698,7 +705,6 @@
   "com_ui_analyzing": "Analyzing",
   "com_ui_analyzing_finished": "Finished analyzing",
   "com_ui_api_key": "API Key",
-  "com_ui_api_key_source": "API Key Source",
   "com_ui_archive": "Archive",
   "com_ui_archive_delete_error": "Failed to delete archived conversation",
   "com_ui_archive_error": "Failed to archive conversation",
@@ -728,8 +734,6 @@
   "com_ui_authentication": "Authentication",
   "com_ui_authentication_type": "Authentication Type",
   "com_ui_auto": "Auto",
-  "com_ui_auto_detect": "Auto Detect",
-  "com_ui_auto_detect_description": "DCR will be attempted if auth is required. Choose this if your MCP server has no auth requirements or supports DCR.",
   "com_ui_avatar": "Avatar",
   "com_ui_azure": "Azure",
   "com_ui_azure_ad": "Entra ID",
@@ -799,6 +803,7 @@
   "com_ui_command_usage_placeholder": "Select a Prompt by command or name",
   "com_ui_complete_setup": "Complete Setup",
   "com_ui_concise": "Concise",
+  "com_ui_configure": "Configure",
   "com_ui_configure_mcp_variables_for": "Configure Variables for {{0}}",
   "com_ui_confirm": "Confirm",
   "com_ui_confirm_action": "Confirm Action",
@@ -1048,7 +1053,6 @@
   "com_ui_logo": "{{0}} Logo",
   "com_ui_low": "Low",
   "com_ui_manage": "Manage",
-  "com_ui_manual_oauth": "Manual OAuth",
   "com_ui_marketplace": "Marketplace",
   "com_ui_marketplace_allow_use": "Allow using Marketplace",
   "com_ui_max_favorites_reached": "Maximum pinned items reached ({{0}}). Unpin an item to add more.",
@@ -1076,7 +1080,6 @@
   "com_ui_mcp_server_role_owner_desc": "Full control over MCP servers",
   "com_ui_mcp_server_role_viewer": "MCP Server Viewer",
   "com_ui_mcp_server_role_viewer_desc": "Can view and use MCP servers",
-  "com_ui_mcp_server_type": "Server Type",
   "com_ui_mcp_server_updated": "MCP server updated successfully",
   "com_ui_mcp_servers": "MCP Servers",
   "com_ui_mcp_servers_allow_create": "Allow users to create MCP servers",
@@ -1087,6 +1090,9 @@
   "com_ui_mcp_type_streamable_http": "Streamable HTTPS",
   "com_ui_mcp_update_var": "Update {{0}}",
   "com_ui_mcp_url": "MCP Server URL",
+  "com_ui_mcp_server_url_placeholder": "https://mcp.example.com",
+  "com_ui_mcp_transport": "Transport",
+  "com_ui_mcp_invalid_url": "Please enter a valid URL",
   "com_ui_medium": "Medium",
   "com_ui_memories": "Memories",
   "com_ui_memories_allow_create": "Allow creating Memories",
@@ -1143,6 +1149,7 @@
   "com_ui_no_read_access": "You don't have permission to view memories",
   "com_ui_no_results_found": "No results found",
   "com_ui_no_terms_content": "No terms and conditions content to display",
+  "com_ui_no_auth": "No Auth",
   "com_ui_none": "None",
   "com_ui_not_used": "Not Used",
   "com_ui_nothing_found": "Nothing found",
@@ -1201,7 +1208,6 @@
   "com_ui_quality": "Quality",
   "com_ui_read_aloud": "Read aloud",
   "com_ui_redirect_uri": "Redirect URI",
-  "com_ui_redirect_uri_info": "The redirect URI will be provided after the server is created. Configure it in your OAuth provider settings.",
   "com_ui_redirect_uri_instructions": "Copy this redirect URI and configure it in your OAuth provider settings.",
   "com_ui_redirecting_to_provider": "Redirecting to {{0}}, please wait...",
   "com_ui_reference_saved_memories": "Reference saved memories",
@@ -1281,7 +1287,6 @@
   "com_ui_select_model": "Select a model",
   "com_ui_select_options": "Select options...",
   "com_ui_select_or_create_prompt": "Select or Create a Prompt",
-  "com_ui_select_placeholder": "Select...",
   "com_ui_select_provider": "Select a provider",
   "com_ui_select_provider_first": "Select a provider first",
   "com_ui_select_region": "Select a region",
@@ -1395,7 +1400,6 @@
   "com_ui_user": "User",
   "com_ui_user_group_permissions": "User & Group Permissions",
   "com_ui_user_provides_key": "Each user provides their own key",
-  "com_ui_user_provides_key_note": "Users will be prompted to enter their API key when connecting to this server.",
   "com_ui_value": "Value",
   "com_ui_variables": "Variables",
   "com_ui_variables_info": "Use double braces in your text to create variables, e.g. `{{example variable}}`, to later fill when using the prompt.",